It's not just SWE's we just see it more in that pool because we mostly (we are on HN after all) swim in that pool.

I've eaten dinner with Doctors (medical) where they've confidently spoken about a subject I am more experienced in than them and they've been hilariously far off the mark, I just nod and ask for the gravy - not picking a fight over a meal.

Prof. Nathan Ballantyne coined the term Epistemic Trespassing to describe it, it is rampant and LLM's just act as an amplifier.

It's like people have a collective fear of just admitting they don't know something, there are a vast number of disciplines/topics I'm not competent or knowledgeable enough to have a meaningful opinion about even if I find the topic interesting, it's just been smart enough to realise that in the end.

Worst case, find the person who does know and ask then both of you might know (assuming you understand the answer of course which isn't guaranteed, I like physics, I'd understand about one word in ten if a physicist actually described it the way they would to another physicist).