i see rude, pompous, arrogant, knowitall comments all the time online. not just in hifi forums, everywhere. would imagine that most everyone does. i figured out a long time ago not to pay them any mind. imho, the truth is that some people get off on the idea that they know X better than everyone else. unfortunately for them, it’s all a fantasy - actual experts and others who can speak with real authority on a given subject aren’t usually jerks about it.
as far as the sexist stuff you see from time to time, it's just sad. the most serious record collector i know is a woman and it is an absolute joy to watch the sweaty knowitall middle aged vinyl freaks lose their minds when she pulls out the rare stuff at dj night. talk down to women if you want to, but try not to cry when they embarrass you
but fwiw, i do think it’s worth drawing a distinction between "rude a-hole" and "extremely opinionated old hifi guy." i’ll give you an example as to why -i recently answered a craigslist ad about some rare sansui gear. the guy who listed it called me up 5 minutes after i sent the email and proceeded to talk my ear off about everything hifi for the next hour. in the course of his lecture (that’s what it felt like) he told me exactly why he thinks my present system sucks, how i was misled, why he thinks amp x and loudspeaker y are superior in every way, and blah blah blah. but here’s the thing: i wasn’t offended! i just remember thinking ok, here’s a guy, a stranger, who’s really into this thing, has been for as long as ive been alive, and who’s gone way deeper than i’ve been. along the way he developed some extremely rigid, but extremely well informed opinions. i appreciated that conversation very much. now, if he had talked to me online like he talked to me on the phone, i could have easily misread his passion (totslly palpable and infectious, in the tone of his voice) for an extreme arrogance and ignored him completely. i'm glad i didn't - he was dropping a lot of knowledge on me and it was terrific. i still like my present setup though.
i also think it’s possible that the surplus of extremist-type debates in hifi world could be a sign that more and more people are getting into this thing. if it’s anything like catholicism, it’s always the converts who are craziest 😂, but they’ll mellow out in time