What is wrong with people on the internet. Like seriously?

I know it sounds stupid and vague but let me break it down a bit to standardise my point.

Here’s an example, You make a comment on a TikTok post, it might be a bit controversial, or it might be fairly standard but either way some idiot feels the necessity to reply and counteract what you’ve said. You end up going back and forth in an argument and that other person begins to become quite passive aggressive, making themselves look like an absolute idiot, not because they’re arguing on social media, but because they’re actually making the most idiotic remarks.

Here’s kind of an example that actually happened. I once saw a video about this “new plane”, new design, new style and a completely newly engineered aircraft overall. Within the video the narrator claimed that Nasa had tested this plane and said that it was “possible” I then done some research and found out that it was true, NASA did say this new innovative aircraft would work and could definitely do what it’s intended purpose is…I then scanned through the comments, most of it was brain rotted memes, none of it actually contributed to anything relevant to the video, but then I found a particular user (who I won’t name), and they had an anime Profile picture (nothing wrong with that but doesn’t exactly scream Physicist or Engineer), They had a few random videos on their page, anime edits etc, nothing of any real intellectual value, their comment on this video was:

“That would never work, NASA have no clue what they’re talking about…”

It then proceeded to explain how this plane couldn’t work. And most people would think this is just “rage bait” or just commenting for the sake of it, but believe me when I say this person was serious. Conversations went back and forth purely because I stated that this particular user seems to think they know better than NASA, and I was honestly stunned at the replies I was getting from this person.

So to summarise, what gets into people’s heads over the internet that makes them think they’re geniuses? Or makes them think they know the answer to something.