I don't know him but with 4 million subscribers he was apparently liked by a lot of people. From what I'm picking up this is an issue that goes beyond whether you loved him or hated him, and into the ridiculous protections on copyrights and the IP laws out there.
From the way it sounds this guy is basically like our own Yahtzee (who started on Youtube) except with a differant target, and a style of humor that doesn't quite appeal to the video game nerd demographic the way Yahtzee does. Like many things on Youtube he's basically gotten smacked by people claiming copyright violations, despite general fair use policies and the like.
I'd imagine if this guy is a Youtube partner part of the reason he got suddenly banned was that there was a preception he was getting away with things other users couldn't (and I mean look at all the bans) because of it.
Personally, I think Youtube needs to lighten up considerably and do more to take the side of the users than the businesses and IP/Copyright holders... at least when it comes to things like Satire, Reviews (even bad ones), and outright parody.
If I had to guess the straw that probably broke the camel's back was one of those viral videos being part of an ad campaign for something that does business with Youtube, with the producers getting all butthurt that someone mocked it to a large enough audience that it couldn't be taken seriously for it's original purpose.