Regarding massproduction of bodyfluids like dairy/milk. Anyone who watches the below non-graphic video has to admitt that is a cruel industry, in my opinion.
If vegans are right or not is not really a relevant question. If you take the moral high ground most people will ignore your arguments. For the same reason I would have never gone vegan somebody put it to me like that. I had to find out for myself (offcourse others fed me with information) how these animals are treated. After seeing this, I know I can't live with myself knowing that I'm facilitating this.