It's unfair to lump most with "left" though. There are quite a number of people on this site which call out sjw bullshit, for instance. I think HN is still much better than tech twitter which is full of woke feminists hating about white straight males and getting away with it. (And I say this I am not even white).
There's definitely a real reason there, which is the same one that people from my parents' generation had when waving around the phrase "political correctness gone mad". I guess you'd rather ironically call it "virtue signalling". But I agree there's not likely to be much chance of having a constructive discussion with someone taking that approach.
Is virtue signaling ironic? I'm not sure what you mean by that point. However, I agree that it's a big turnoff to engage with someone using that language because it seems as if they already have their mind made up.
Perhaps the most commonly perspective here is one based on falsifiable evidence. My decades of exploring faith were entirely evidence free, and I'm glad that way of thinking is passing away.
This is one of those instances where I find it difficult to accept honesty. The entire purpose of the public school system - in EVERY country - it to make you accept stuff without evidence, or AGAINST evidence.
E.g.: the Earth revolving around the Sun, the existence of Black Holes, the Earth being 5 billion years old and so on. I have daily evidence against the first, and no evidence for the others, all of which are accepted by everyone "because scientists / professors / everyone else says so" and any attempts to argue against it are ridiculed.
Let's not even go into Global Scamming, which has reached religious levels of hysteria. I mean, "the world is ending, give us money" is basically copied from the Catholic Church.
School shouldn't appeal to authority either. They should teach the evidence, and where that's impractical the conclusions of experts (with citations). School curriculum is often updated yearly.
If you doubt the sun is at the center of the celestial system there are some experiments you can do yourself to test that conclusion. Proving or disproving black holes may take significantly more effort.
What distinguishes religion is blind appeals to authority and claims about ancient, sacred truths which cannot be falsified.