It's not cool to call someone out, but it's even less cool to have to. What else was he supposed to do? Have a nice reasonable talk with a troll?

Better that he's making people aware rather then continuing a fight that was disrupting a service for others.

Agreed on the first two points.

But what's wrong with calling people out on a public forum? There are lots of people doing bad things in this world, and the only cure is for us to confront them and out them.

It's the closest thing we have on the internet as "speak softly and carry a big stick".

Github is a company. Remember, they make money, have employees, and are a corporation. I didn't say Tom Preston-Warner was an asshole, I said github has a problem with how their collaborators work and they refuse to fix it. Without people pointing out flaws like this and reporting on companies like this we'd all just be a bunch of corporate slaves buying their random crap.