eating a vegetarian diet is not less healthy than eating a meat-based diet.

I don't remember which one it was but there is some vitamin you can't get from plants alone. I think it was a B vitamin but I don't recall. Just eat what you feel like eating, your body knows what it needs. A lot of people are having great results from a paleo diet which includes loads of bone broth, that stuff is great for you.
I believe that your latter conclusion about them is probably correct, I can't imagine what a dick I would be if I could never get a goddamned cheeseburger. The Dalai Lama eats meat ;)