My impression is that of LWers, vegetarians are the most common group (though perhaps there are lots of sleep-deprived people).

But still not very common. Vegetarian LWers would be, what, 10% maybe? (Not sure any surveys have covered it, but I don't see it discussed very often).

Overall, I was disappointed with taking a qualified statement

/shrug

That's Luke's description, not mine. I've edited the page to include specific citations for each group and some PDF links, incidentally.