I think it's precisely because he's been so overexposed that stuff like this comes about - Obama has practically become a character in his own right. This is more a satire of 'Obama the Legend' than a direct celebration of it (although I think it's pretty clear that whoever wrote the thing is on his side.) And frankly, the fact that most of the prominent rightwing politicians for the past eight years HAVE basically been 'vicious evil warmongers', to the point where their own party said 'enough's enough', should provide a pretty good reason why none of them got a comic like this. They didn't deserve one, and anyway, they were parodied by pretty much everyone already.