To illustrate with an extreme: If we happened to be hard-wired by evolution to be tremendously predisposed towards genocidal behavior, would that make any acts of genocide we commit morally acceptable behavior?
Halfway through my response to this, I realized that someone had already written it, and in a much more entertaining fashion. So I'll just point you to his post instead:
We also have hard-wired general memory and reasoning faculties.
"We are not animals."
We are not base animals, to be sure. Neither are we angels of pure logic.