Sanctimony is feigned or hypocritical righteousness or piety. Could you explain why this describes vegetarianism? Of course some individual vegetarians are sanctimonious, but you seem to be generalizing to the practice of vegetarianism.
You suggest "lobbying the meat industry to change its ways, or supporting the development of synthetic meat." Could you tell me more specifically how to do that? I might try it. Regardless, I don't see how that makes it a worse idea to reduce my meat consumption.
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: