I see your post and your condemnation as somewhat one-sided. I am an older cis white male who is not a fan of SJW, radfem and double standards in any areas, I cannot help but notice that your reading of the guidelines is skewed by your personal views and prejudices. Let's look at the analysis of the guidelines that you linked to, by Stephanie Pappas, rather than at your interpretation of them. Here are some quotes and comments. The guidelines themselves are here.

[Men] are the demographic group most at risk of being victimized by violent crime. They are 3.5 times more likely than women to die by suicide, and their life expectancy is 4.9 years shorter than women’s. Boys are far more likely to be diagnosed with attention-deficit hyperactivity disorder than girls, and they face harsher punishments in school—especially boys of color.

This seems like a statement of facts not at all unsympathetic to men's struggles.

“Though men benefit from patriarchy, they are also impinged upon by patriarchy,”

I hate when people use the notion of patriarchy to invalidate personal experiences of men, and there are plenty of other forces, at least in the West, that make life harder for men that feminism tends to discount, the above statement, if corrected to read “Though many men benefit from patriarchy, many are also impinged upon by patriarchy,” would match the experiences of most people. One ought to avoid the sweeping statements like "you are a cis white male, therefore you are automatically the beneficial of "patriarchy" and are complicit in the structural oppression of women", but treat each person's experiences individually, while being aware of the general trends, of course.

Prior to the second-wave feminist movement in the 1960s, all psychology was the psychology of men. Most major studies were done only on white men and boys, who stood in as proxies for humans as a whole. Researchers assumed that masculinity and femininity were opposite ends of a spectrum, and “healthy” psychology entailed identifying strongly with the gender roles conferred by a person’s biological sex.

This is not an unreasonable assessment of the pre-feminist state of affairs.

Once psychologists began studying the experiences of women through a gender lens, it became increasingly clear that the study of men needed the same gender-aware approach

Not sure why anyone would argue with that.

The main thrust of the subsequent research is that traditional masculinity—marked by stoicism, competitiveness, dominance and aggression—is, on the whole, harmful. Men socialized in this way are less likely to engage in healthy behaviors. [...] the more men conformed to masculine norms, the more likely they were to consider as normal risky health behaviors [...] This masculine reluctance toward self-care extends to psychological help.[...] men who bought into traditional notions of masculinity were more negative about seeking mental health services than those with more flexible gender attitudes [...] mental health professionals need to be aware that men are often reluctant to admit vulnerability [...] “Because of the way many men have been brought up—to be self-sufficient and able to take care of themselves—any sense that things aren’t OK needs to be kept secret,” [...] Though men report less depression than women, they complete suicide at far higher rates than women, and the numbers are moving in the wrong direction.

All of the above matches my personal experiences and has no hint of "science denial."

questionnaires on depression and other mental health problems are missing something when they garner answers suggesting men don’t struggle with these issues as much as women

I see this as raising alarms about men's psychological health, which is quite timely, especially in the face of pervasive invalidation of men's struggles in the media.

“Boys and men of color [are] dealing with all their hurts and their struggles in ways that are consistent with masculinity,” Liang says. “So, ‘be tough,’ and ‘don’t show your hurts.’ And they have to do this in a system where their behaviors are looked upon more negatively than boys and men from different groups.”

Again, seems like a reasonable description of the reality, doesn't it?

The post also acknowledge that the male/female dichotomy is outdated and recognize the rich spectrum of gender identification:

Today, transgender issues are at the forefront of the cultural conversation, and there is increased awareness of the diversity of gender identity.

Pappas then talks about the struggles of gender-nonconforming people, especially those that the society pigeonholes as males, and concludes the topic with

“There is a lot of diversity in the experience of men and masculinity, between groups, within groups and even within an individual,” Liang says. “What’s important is to understand that despite all of this diversity, boys and men may experience incredible pressure to live up to these rules around masculinity that they may have learned within their own cultural context.”

Again, the emphasis is on better understanding, something I can only cheer for.

Next the l talk about how to better help those who "would never dream of seeking mental health treatment". Sadly, this is where they are the weakest:

First, clinicians must be aware of dominant masculine ideals, and cognizant of their own potential biases. Second, they must recognize the integrated nature of masculinity, and how factors ranging from spirituality to ability status to age and ethnicity interact. Mental health professionals must also understand how power, privilege and sexism work both by conferring benefits to men and by trapping them in narrow roles. They should consider how stoicism and a reluctance to admit vulnerability hamstring men in personal relationships, and they should combat these forces, in part, by encouraging fathers to engage more fully with their children.

This is painting men with an overly wide brush and succumbing to the stereotypes. While some men certainly fit the above description, the situation is far from universal, at least in the modern Western societies. Some statements are more reasonable:

They should encourage men to protect their own health. And they should offer services sensitive to the socialization that men have undergone, while fighting against homophobia, transphobia, racial bias and other types of discrimination in institutions such as the criminal justice system.

They encourage the mental health professionals to look past the veneer:

When men do seek help, clinicians need to be aware that aggression and other externalizing symptoms can mask internalizing problems

The "Supporting the positive" section is a bit of a mixed bag. On the one hand it starts with "important to encourage pro-social aspects of masculinity," on the other, they attribute the largely gender- neutral traits like self-sacrifice and stoicism to mainly men. Men should "discard the harmful ideologies of traditional masculinity (violence, sexism) and find flexibility in the potentially positive aspects (courage, leadership)" seems a bit overly gender normative, and not very reflective of the realities.

Pappas then backtracks and says that

there’s less daylight between what’s expected of men and what’s expected of women than a glimpse at media and culture might reveal. About a third of the traits that people consider to be positive aspects of masculinity, such as sacrificing for others and having strong morals, are actually expected more from women than men when researchers ask both men and women [...] Indeed, when researchers strip away stereotypes and expectations, there isn’t much difference in the basic behaviors of men and women.

This is as moderate and reasonable a position as one can hope. I don't like the concluding sentence, though,

And if psychologists can focus on supporting men in breaking free of masculinity rules that don’t help them, the effects could spread beyond just mental health for men, McDermott says. “If we can change men,” he says, “we can change the world.”

mostly because it specifically targets men. If phrased as "supporting everyone, including men, in breaking free of gender rules that don't help them..." I would have no problem with it.

But this week, my outgroup has decided to launch an all-out attack on men, in the form of the American Psychological Association’s guidelines for practice with men and boys. It is a dangerous piece of science denialism published by a powerful organization, with the potential to hurt countless people.

That's a pretty ironic sentence, given that the link doesn't go to the APA’s new Guidelines for Psychological Practice With Boys and Men but to an article about them. Before charging other people with science denialism it would be helpful to understand what a guideline happens to be.