I eat meat but I fully expect it to be killed humanely. I grew up on a farm and our animals were treated well even if you can't guarantee that when you buy meat.

There's a difference between animals being killed for food humanely and animals painfully slaughtered for fun. Just because it's been done for a long time doesn't make it right. People have been murdering each other for a long time too but if someone killed someone you care about I think you'd be against that.