Good point, I should not have assumed that repeatedly admonishing someone toward the same line of thinking through arguments based on rationality would be consistent or logical.

How is advocating that someone be consistent not advocating consistency?

In response to your second argument, the stated example is very similar to proselytizing in that you're attempting to bring your friend around to a way of thinking that you consider to be true and correct. Presumably because you also believe that it will improve their life. So if the end goal is to help them become a more emotionally stable person, then does it matter if they get there with rational or Christian teachings?

If the, presumed, end goal of this is to help your friend live a happier life then what is the effective difference between::

"Logically, there is no reason for me to be angry that I can not find my comb. This isn't a big deal."

As opposed to:

"The comb is a just a temporary material object whereas I am an immortal spiritual being. Why get angry over it?"

Squick? Oh, it's some TVTropes term. That's a bit excessive, it is only mild bemusement on my part.

Why should we presume the person trying to persuade their friend in this example is objectively correct in knowing what is both the appropriate and correct way for their friend to behave?

You can shorten it to: "Don't be discouraged when your proselytizing of rationalism is ineffective the first time, just be consistent in your message." Honestly not seeing much of a difference in the article if you replace every instance of "rational" with "Christian."