The fundamental tenet of nearly every spiritual tradition is to do good; don't cause harm or inflict unnecessary suffering. Help others whenever possible. This all sounds good in theory but putting it into practice is another matter entirely.
In the modernized West, food of all varieties is available to people of all incomes, and yet Americans consume more meat than ever before in history--even though they know that animals are virtually tortured in the process. I don't understand this willful ignorance. I'll paraphrase Thich Nhat Hanh and say that a hamburger is pain. We support cruelty when we buy factory farmed meat.
Another example of the same principle: although many of the white Americans who voted for Donald Trump may not actually be racist, they are okay with racism. When Muslims or Mexicans are persecuted because of racist legislation that Trump passes, Trump voters are responsible for that injustice. They may pretend that they aren't or argue otherwise, but they are accomplices to racism and discrimination.
A large part of contemplative practice is about being honest--owning oneself and one's actions. If we endorse racist politicians, we are permitting racism. If we eat meat, we are a contributing to cruelty. Our actions and their consequences are our responsibility. If we poison the river, we are responsible for all of the harm that it causes--not just immediately, but generations from now as well.