You are absolutely right, this has been my experience too. Pointing out what you did about (lack of) sterilising and (importance of) mucosal immunity usually got you downvoted here up until recently. It doesn't matter what your political persuasion is (I am, or at least I was, going into the pandemic, a left liberal), the idea that the vaccines would end the pandemic if only enough people got 1, 2, 3 or more doses was gaslighting from the beginning, probably arising from flippant remarks from politicians when asked for target dates to lift lockdown restrictions - "when X% are vaccinated!". And the idea that this was never what was being said about them this time last year is also gaslighting that's happening right now.
The problem is that this is a very nuanced subject. Everyone thinks they know what's going on, because they've been told it's simple: get vaccinated/boosted, work from home and do as we say and this will all be over. Much of the data being used to justify this was one or more of badly collected, badly analysed or badly interpreted by dishonest politicians, journalists, scientists and members of the public pushing their own (or their bosses') agendas. Instead of opponents' arguments being heard and countered in public ("sunlight is the best disinfectant"), they have been deplatformed under the auspices of "public safety". Scientists have lost their jobs for saying something to counter the narrative - it has become illegal to disagree with the scientists the politicians listen to, under punishment of losing your livelihood. It has been a total shitshow that has exposed how corrupt the whole system is. It has made me quite depressed at how little we've apparently learned since the last century. I thought we were living in the age of science, but what we have right now is far, far from it; maybe we should call it the age of misinformation - driven by humans' psychological maladaptation to their own incredible invention, the internet.