A sentiment which in many cases is fueled by insecurity (laugh at these people with me, please ?), guilt (wh-wh-what...there's nothing wrong with eating meat ! I'm not a bad person, really !), laziness (everyone else makes fun of veg*ans == easy target), and general immaturity.

Most anti-veg*an jokes/rants rely on a few points:

Animals are dumb/dirty/ugly/smelly !
If they're so nasty, why eat them ? Just say "Them animals shore taste good !" and be done with it !

Veg*ans are murdering vegetables !
If you're so concerned about the innocent, immobile plants then I hate to break it to you, but when you eat herbivorous animals just think of the millions of poor little grasses that died for your one pound of flesh ! They eat many times more helpless plant victims than any veg*an could. So stop perpetuating the demand for these walking plant holocausts ! The more meat you eat, the more innocent plants die !

Our bodies are built to eat meat !
So are pandas, and you wanna' compare your own measly canines to a mountain gorilla's ? And for that matter, our bodies have parts made for sex, but that doesn't mean everyone should or does get it.