He has a tendency to blow things out of proportion and to air these problems publicly, using inflammatory language when most people would choose to use more direct channels.
All of the incidents I have read about have been legitimate problems, but I personally would have handled all of them very differently.
This particularly incident, for example, probably could have been solved simply by e-mailing github. In Shaw's case, he assumed they were in on it. I'm sure he had his reasons, and certainly the troll behind dongml gets no sympathy from me but I don't think blaming github and dragging them into this was appropriate.
Honestly I've never understood why some people (seemingly) defend him unconditionally. It sounds like he's a really stand-up guy in real life, but I'm still willing to call out my friends when I think they've gone too far.
-Niki Yoshiuchi