The problem is, he's assuming everyone else is pissed and we don't know that.
The thing is, there's no reason for anyone to get defensive. Nobody was really painted in a bad light in what has been shown so far. One of the main purposes of the documentary is to justify the band's decision in the eyes of most fans. Wheher we agree with the decision or not, I think DT wants us to say "at the end of the day, I see why they chose the person they did." So of course they are going to show some flaws in the ones who weren't picked and not highlight the flaws of the person who was. Some of the flaws are technical; some are just chemistry; some are personality. Nothing wrong with any of that. And none of the flaws are major. With Roddy, he wasn't as enthusiastically into it as others, didn't want to give up the lifestyle he has, and doesn't really work well in the confines of a process where he is given a bunch of riffs in odd time signatures and has to jam them out before just being able to chew them over in his mind and digest them. Nothing wrong with any of that. And he was still portrayed as a world-class drummer and pretty cool guy. So I don't see what the fuss is.
He's probably saying things from a biased perspective and sounds like he has the kind of personality where he assumes too much about other people (such as what the other drummers may have been told are may be thinking). Okay. He's not the first musician (or first person, for that matter) to have that personality. And keep in mind that he is posting all this on the internet, where it is easy to misconstrue tone and blow things out of proportion. I could be wrong, but honestly, I don't think he's all that upset and I don't really see a problem with anything that has been said or done by anybody.