Under this view, there is no such thing as objective morality, and thus no objective good and bad. It's all about opinions and that's all it ever could be about. The fact that you're "wired" to avoid pain doesn't imply it's good to do so.
The fact that atheists still, on the whole, want good things to happen to themselves and to other people is an often-overlooked leap of faith.
I'm not sure how that follows. Atheists are writed to to avoid pain and stimulate pleasure centers, those things are directly influenced by their actions, which just happen to correlate with "good" and "bad"" (or, more correctly, opinions of what's good and what's bad are based on those stimulations), and thus atheists want good things to happen, simply because the are wired like that. Why does faith have to enter into this?