The most important reason to go vegan is to recruit revolutionary animal activists. To educate, to enlighten, to recruit, and to inspire others to lock arms with us in solidarity.
All of the other reasons to go vegan will not make a difference in the world. Animal suffering, global warming, environmental degradation, world hunger, wildlife extinction, rainforest clear-cutting, human health, et al, will never be achieved by voluntary veganism, as we are losing ground in the general population.
Capitalism is selling more meat, dairy, and cruelty then we are selling compassion, justice, and the future of the Earth. They have the advertising agencies, the television stations, the newspapers, the billboards, and the money to do so, money earned from the blood of our fellow Earthlings.
Carnists are having children faster then we are recruiting vegans. Animal slaughter is expected to double in the next 25 years.
The only hope for animals, and for the survival of life on Earth, is social revolution.
Political revolution might work, and we should pursue it by electing the most liberal and leftist candidates for office, with an eye on bringing down the system should politics fail.
Capitalism and our legal systems are the reasons 50 billion animals die in slaughterhouses each year. Capitalism profits on the horrors, and our legal systems permit the horrors.
We must join with other enemies of the corporate state: social justice advocates, occupiers, environmentalists, prison reformers, anti-globalists, peace activists, women, the LGBT community, ex-convicts, urban gangs, and leftists around the world, to bring down capitalism.