I don't think you can really tell how an actor gets there by their end performance. And their behavior off screen is also unrelated. It seems like you have a hard time separating the person from the performance. Which is understandable, but something you should keep in mind when making assessments of any actor.
He certainly sounds like he's annoying to work with. Which also makes me wonder why people would put up with him. Good actors aren't rare, there of plenty of other options.