On the other side of things, being a fan of science fiction does not mean that one can't be critical of the players of the genre. Science fiction is not about accepting everything as quality; it's not some bizarre ultra-socialist experiment to give everything the same value. Get over yourself. There are a heck of a lot of science fiction fans who hate Star Wars or Star Trek; such is part of the dynamics of the SF fan community.
So, no, I am not an anti-SF fan based on my daring attempt to call Avatar out for its shoddy storytelling; I am an actual science fiction fan, but with different expectations of the genre. I want science fiction that is capable of giving me something more than flashy CG, recycled plots, wooden characters, and inconsistent universes. Maybe Avatar will prove me wrong and be none of those things, but right now all the reviews are confirming everything I've said thus far: it's a story I've already seen twenty-five times before, in film, and it will be so overwhelmed with computer graphics that people who have never been on acid might think they've been duped into taking an illegal substance. That's not the kind of SF I want. Filmmakers need to learn from George Lucas: computer graphics do not make a film, and if you're going to spend so much money making a movie pretty, you should spend an equal amount in dollars and hours on actors, directors, and writers to make sure that what you have is a good product, not just another flashy action movie.
But, again, everyone is going to see Avatar anyway. It doesn't matter what I think. It's going to make millions, but in ten years it probably won't be remembered as anything but a vague footnote.
That is all.