Do you believe that the first vegan/vegetarian you can think of really know what their True Rejection of animal eating is?

I don't believe in the concept of "True Rejections" in the sense you are advocating it here.

Most vegan I know don't follow that paradigm because of a cognitive moral argument but because of something they would call compassion for animals. Compassion happens to be an emotion and no logical argument.

Many vegans I know also think that being a vegan is healthier and like the feeling that the change to that diet brought them.