I have the same problem as Linus that I'll go overly dramatic and nasty in calling people stupid in replying online, something I don't do to people's faces. The more strongly I feel about something, the more likely it'll happen.
It's like some sort of social filter doesn't get applied, one I use when I'm speaking, but it just gets skipped when typing. When I read back those posts, I'm embarrassed, not proud of my "technique".
It's my problem, not the victim's. Luckily, because I'm not internet famous, those sort of posts get downvoted and I get some sort of feedback loop. But Linus gets defended and the cycle continues.