I believe it’s similar to road rage. You are very restricted in your way of communicating and cannot read the other’s emotions at all. That means you have to interpret a lot more and that is done in your own state of mind, meaning you can easily take offence where non was meant and the other has no chance to de-escalate as they would in face-to-face communication.
Ignoring trolls and actual assholes, that kind of misinterpretation happens so easily, I’ve often seen it among friends (via chat) and my own mother raged about an email I sent her (which was then de-escalated by a single sentence in a phone call). That’s also the reason, sarcasm works so poorly online.
Get on your own lawn:
touch ~/grass