I do think this has always been the case, Jerry Pournelle funnily enough made a very similar observation back in 1986 (https://en.wikipedia.org/wiki/Flaming_(Internet_term)#Histor....)

People who post on the internet are outliers, something like 98% of message board users lurk, can't remember who said it but someone summed it up as "everyone you talk to online is crazy". The reality is life is boring a lot of the time and I've always seen online interaction not as a substitute for social life but with no expectation. Sometimes you get good conversations, often you don't.

There is more negativity in terms of volume which has a quality of its own because it seeps more into real life than in it used to, but honestly some conversations in the olden days were worse.

https://old.reddit.com/r/slatestarcodex/comments/9rvroo/most...