Pay attention to the downvotes, and browse HN with "showdead" turned on, and you'll see that HN stays the way it is in large part due to aggressive exclusion of those who can't stick to society norms up to an including the metaphorical "door guy" (bans).
Self-filtering is a start. But pretty much all cliques and scenes also have lines you will get ostracised if you go past. The extent of their reaction if you will vary, and sure, there's a difference between proactively judging you based on appearance and retroactively judging you by actions, but in some scenes your appearance is part of the game. That sucks if you don't fit in, but it also sucks for those who want something specific if you're that one person who can't self filter and insist on ruing the experience for everyone else.