I really think a large part of the problem has to do with inherent limitations of online forums + typical personality quirks of a pinhead.
Quite frankly, a lot of us pinheads are smartasses with irreverent senses of humor, and we tend to derive entertainment and pleasure endlessly taking the piss out of each other, with lots of good-natured ribbing and shit-talking along the way. This is all great fun and good for a lot of laughs, and engenders friendship and comradery when the interactions occur IN-PERSON in normal settings (parties, arcades, expos, bowling alleys, pubs, etc.).
Online, all bets are off though, because none of the non-verbal stuff that normally serves during face-to-face interactions to provide "context clues" that the ribbing is good-natured and intended to be fun and light-hearted translates well in mostly text online interactions (judicious use of emojis can help a little, but is woefully inadequate to fully compensate). Therefore, things can get misinterpreted and incorrect conclusions are drawn, and hurt feelings, anger, and resentment can be the result, leading to some of the malignant posting and sniping that is sometimes seen here. Also, it's easier to suspend whatever form of "bad mood" we happen to be experiencing in a social/party/pinball setting than it is sitting alone in isolation with a tablet or computer, which no doubt contributes to a more positive vibe and less risk of being offended.
I don't know what the solution is other than to individually try to extend grace and liberally give each other the "benefit of the doubt", while also learning to retrain our brains to be a little less quick to jump into "defensive" and "counter-attack" mode (IOW, develop thicker skin).