I don't really have an opinion one way or the other. I've never played any of the Diablo games. I watch Pat on occasion if the topic is a subject I'm interested in, but I'm not enough of a fan to go out of my way to defend him. From what I've seen, his response wasn't any more offensive or extreme from what he normally says when he takes a stance on something. I get that Diablo fans are pissed, but I could never imagine going to a convention just to hear an announcement before it's on the internet. While any fan certainly has the right to be unhappy with their presentation, in general, they clearly overreacted.
Also, unless a video has nudity, or some extreme hate speech, reporting it will do nothing.