I can think of reasons to be honest that have nothing to do with the total amount of honesty in the world, but I don't see any reasons to prevent animal cruelty that are unrelated to the amount of animal cruelty in the world.
Actually I agree. But what we eat does affect the amount of animal cruelty in the world, albeit a very small amount (I should have avoided the term negligible) compared to the sum of animal cruelty, or per capita animal cruelty.
Furthermore, my experienced utility function is quite a bit like yours, where we appear to differ is that I consider mine flawed and I'm working to change it. Therefore I shut up and multiply
I am only mostly vegetarian, and I probably never would have come that far if I didn't fall into a social circle which had a lot of vegetarians. My guess is that the marginal benefit of two randomly selected people cutting half the meat from their diet is slightly greater than one person becoming strictly vegetarian. I think there are many things which are more important than choice of diet, but this does not mean we should ignore the effects of our diet.
I have noticed that among philosophers, vegetarianism of one form or another is quite common. In fact, I became a vegetarian (technically a pescetarian) myself partly out of respect for an undergraduate philosophy professor. I am interested in finding out if there is a similar disproportion in the Less Wrong community.
I didn't request that this go into Yvain's survey because I want more information than just what animal products you do or don't eat; I'd also like to see nuances of the reasons behind your diet. There are a lot more shades than carnivore/vegetarian/vegan - if you want to be a vegetarian but are allergic to soy and gluten, that's a compelling reason to diversify protein sources, for instance. I'd also like to hear about if you avoid any plant foods (if you think they're farmed in a way that's environmentally destructive or that hurts people or if you have warm fuzzy feelings for plants, maybe). Here are some questions that come to mind: