This article is interesting but they are probably overthinking it. I think it's 80% or more due to the "road rage" effect. That is, people who aren't face-to-

This article is interesting but they are probably overthinking it. I think it's 80% or more due to the "road rage" effect. That is, people who aren't face-to-face don't humanize the other they are interacting with. There's also the "alcohol" effect, which is to say that someone speaks recklessly when they aren't afraid of getting punched for it.