It depends on the person. I don't think that you can say that all vegans are compassionate (though they do live a compassionate lifestyle) and that all omnivores aren't. Some are some aren't. But because I have a very compassionate nature I was not hesitant in the least bit to become a full on vegan (though from the moment I tasted meat for the first time I was vegetarian-- I hate the taste). I think that the problem is that a lot of omnivores just don't know the pain and suffering animals go through. They just don't realize, and many for many omnivores, when they learn-- they want to act upon it. Some people though really are heartless on the topic and that makes me very sad.

meat eater: "You need meat in your diet." me: "yeah, because I love clogged arteries."

My parents thought I was being rebellious or trying to prove a point or something. They finally realized I was serious about it as the years went by. haha Now 4 years vegetarian and 1 year vegan! Never going back! :)