>In all fairness, many people aren't going to want to watch, read, or associate themselves with Twilight after viewing this video.
Which is exactly the point. The purpose of copyright is not censorship. That's why parody and criticism are the core of fair use.
I think the fair use factor that talks about the effect on the market for the work is kind of confusing if you don't have the context of the associated court decisions: It refers to whether the allegedly infringing work competes with the original, not whether it makes everyone stop buying the original through effective criticism.