The main reason why I don't usually talk seriously about what I'm an expert in on Reddit is that I sometimes can't deal with the cringe from the replies, usually it's ok but it's been really bad a couple times and that just pushed me off. Now when I am commenting on something I consider myself an expert of it's usually jokes and sarcasm.

Reddit is seriously full of teenagers LARPing as adults, or adults stoned to the point where they basically are behaving like teenagers... not that I have anything against that. When you start seeing it like that it's much easy to get what you want from it, like when I realized The Economist is mostly idealist very smart mid 20s college graduates on their first serious job.

Places like HN and Reddit are fun for things one has an understanding of but not expertise in. You can hash out arguments, get corrected when wrong and genuinely learn from the experience. For matters I have expertise in, I know the other experts. They’re more rewarding conversation on those topics.

In their defence, often there's no way of telling who is expert and who is faking.

Though it applies to almost everywhere online.