I question the assumption about immunity. Something that never goes away is very different to an exceptional event. The flu is never leaving us because we would need a universal vaccine that was administered at birth for the entire human population (animal reservoirs for coronaviruses are many). We don't have 8 billion doses of any vaccine, let alone one that works universally and for sufficient duration, and we don't have the infrastructure to reach everyone anyway.
There are lots of reasons not to complain. If your life has already been destroyed there's nothing to go back to. People in ruin have other things that are more important than getting on twitter to bitch. Much damage has already been done, everyone knows that nobody responsible will ever pay for that. Everyone knows that plenty will never recover. Everyone knows that ultimately nobody cares, and that the second this is out of the public (and especially political, not that they aren't milking it for all its worth) consciousness it will be nothing more than a footnote.
Secondly, given the filter bubbles we all live in the odds are that there's plenty of complaint that you are never exposed to. The majority of my trusted media and commentary sources have been complaining since the beginning (The Mostly peaceful protest meme springs to mind as an example of the severe disconnect that the tribes have with each other). So from my perspective this exists, and you either aren't exposed to it or you see it and dismiss it (like we all do). This isn't across your media because your media is heavily filtered and biased (like all media is).
Getting a clear picture these days is a lot of work, and that's something a lot of people don't want to do - and that's before they start redpilling and blackpilling themselves with whatever they dig up. I know that the more I find out about what's happening in the world the more disgusted and demoralised I get. All news is inherently biased against whitepills, and so is our very biology. We evolved to pay more attention to threat.
Immunity certificates are the kind of thing that those that favour authoritarianism want. Anyone with half a brain can see what a disaster that would be, but when people are a part of the group that is on top and enjoying punishing others they rarely stop to consider logical consequences (ie. make shackles, have them used on you). What can you do? There's no vaccine for stupidity and there never will be.