Not all vampire mythology is the same. Twilight's vampires are not allergic to the sun, nor do most of the those things (garlic, holy water) apply to them.
The book is essentially a love story, the vampire thing is just an aspect of it. If you're looking for something like more traditional vampires, you're going to be disappointed because you shouldn't expect that from this.
Seriously, why post a bunch of negative comments in a place where the fans come to talk about it?
I've heard all this crap before and it could apply to most vampire stories where they fall for a human.