Nice tongue-in-cheek comment there. But the fact that it isn't true is an indicator of the kind of cognitive dissonance that meat eaters manage to maintain with no effort at all. Because many moral arguments against killing and eating human beings logically extend to apply equally to eating "higher" mammals (at least) such as cattle, sheep and pigs. Yet meat eaters will often claim that human beings are on a completely separate plane when it comes to eating them, for reasons that few can manage to articulate.
Sounds like you have only known pseudo-vegetarians whose vegetarianism is all about them and not about what they eat. So, they're vegetarian for their own health, or because they want to lose weight, or because they think they'll look better on a vegetarian diet, or because they think their friends will admire them for being nice to fluffy animals, or whatever. Essentially, vegetarianism is a phase or a fad for such people.
I've come across quite a few self-proclaimed "vegetarians" who still eat chicken, or who will argue that fish isn't really "meat". Obviously, these people haven't quite got the whole concept down pat.