You're hardly the only person I know who is grossed out by meat. To me, though, that's not just a mental issue, it's mental illness. We are omnivores.
If a person grossed out by meat suffers from mental illness, then so are people grossed out by genocide. If we simply follow our genetic instincts, then keeping ourselves or at most our tribe alive is our prime directive, and we should kill, butcher, or massacre everything or anyone that helps us achieve that goal.