I eat meat because I don't really care about being ethical.
More to the point, my moral center is dialled up to somewhere between Fluttershy and Gandhi, and if I thought about the big picture, was fast enough to think about things before I do them (I'm not good at thinking in a social environment, I can hardly time saying "hi" right or get a correct response to a greeting), and actually cared about what my own sense of right and wrong has to say about stuff (since I don't believe in objective morality, just the morality in people's brains including my own), I would act something like that.
The issue of eating meat gets hit with the first and third of those - I don't really mentally associate a cooked piece of meat with the no-longer-living animal it came from, and because I like the taste of meat I don't feel that much of an incentive to correct that, because then I'd feel too bad about eating meat to be able to and all I'd gain is more consistency in my worldview, which isn't a very fair trade no matter how OCD you are.