Habit, tradition, (Small-c) conservatism. It's true we (most of us) don't absolutely need to kill animals for food. On the other hand there is a vast human mom

Habit, tradition, (Small-c) conservatism. It's true we (most of us) don't absolutely need to kill animals for food. On the other hand there is a vast human momentum in the direction of raising, killing, and eating animals. That doesn't change overnight, or even in a generation or 5. It takes a long time to change such things. My theory: It's for a similar reason that homosexuality has been taboo for so long. In the beginning, tribes needed to procreate in order to survive, and homosexuality didn't help with that, and it may have hurt. So it was written into old books: go forth and multiply, and don't have fun with those of the same gender. That won't produce offspring. But now the challenges of survival do not involve "not enough offspring". So we no longer NEED to worry so much about homosexuality, not for 1000 years. And yet, the belief and habit of mind continues.