Most other people here are discussing the degree to which he was/was not a bully. You've actually hit the nail on the head: this bug submitter is _absolutely right_ (old bug and new bug). Why not also remap ctrl-c to paste and ctrl-v to delete line?
I'm not sure if it is a sense of humor thing, but I don't get anger from his bugs at all. A bit of frustration, and colorful language. But that's not rage.
He's profoundly wasting his time by bothering to talk to Mozilla developers. I learned long ago that they are extremely cliquish, and don't care what you think. They will do whatever they feel like doing, whether or not it makes sense. Personally I quit using thunderbird when they pushed an updated, it broke the client, and their reply on the forum was more or less "too bad, sucker".