what is it about this guy that people feel the need to back him so hard?
It could have something to do with the fact that his movies are tailor-made for cinephiles (in the sense that there are so many references and homages) and so a large contingent of his fans are people who take film very seriously and have seen and absorbed way more movies than the average person. I think these people tend to identify very personally QT himself since he is such a film nerd, and can get really defensive about his stuff as a result.
Well, I, for one, liked the part where they shot Hitler's head off.