I've always had a habit of remembering "x tells me y is true" instead of "y is true" when x tells me y is true.

Impressive if true- the best way to test this might be playing a game like The Resistance...

I'm vegetarian for carbon efficiency and because the animals that produce most of our meat have negative utility from awful conditions. I don't think sentience is the right standard; is there a good past lesswrong discussion about that?

The last one I remember started off with a really confrontational post, and ended up being an angry discussion; I don't think I'll find and link it. I think you could write a better one, and I'd comment on it- I think your points are good reasons to cut back on meat and to strongly prefer small farms over industrial-scale meat (at least for pork, since pigs are the most sentient of our livestock), and I do both of these, but I don't find it worthwhile to go completely vegetarian.