People who eat meat get very defensive with vegetarians and vegans. Their discomfort makes them engage in a lot of unpleasant behaviors, including ridicule and deceit.

Humans are not omnivores. We are herbivores and our physiology proves it.
Here's a link to a synopsis of the facts.

There are other articles about the same thing and you can search for more information. (I just used humans are herbivores not carnivores and grabbed one of the first links I was familiar with.)