are not incompatible. For instance, our eyes don't happen to be good visual organs by chance. They have been designed for the purpose of seeing by milions of years of natural selection
2) Humans are designed to be able to eat animals (and to enjoy it, if they are nicely cooked). We are generalists, we are designed to be flexible, to cope with a wide range of habitats and food sources (mostly by building tools, but that's another node). We are also able to eat each other, kill each other, etc. Just because we can, doesn't necessarily mean that we should. Just because we like it doesn't mean we should, either.
More importantly, we are capable of living on a meat-free or nearly meat-free diet for most of our lives without much trouble. Human beings are not designed to require eating animals.