I think a big issue with lots of vegans is that they don't know how capitalism works. People think that capitalism is just supply and demand, so if people don't buy dairy or meat less animals will be slaughtered. But that just isn't how it works. They can just raise the demand by making Got Milk campaigns and lobbying the government. Not buying a steak at the grocery store is not going to change the behavior of a multi-million dollar company even if hundreds of people go vegan.