To claim that our morality can be explained by science is one thing, but you can't then claim that things that correspond with that are 'empirically moral' the way science is usually used to claim empirical facts. It is not an empirical fact that suffering is wrong; it might be a scientifically justifiable opinion, but it is still an opinion because the word 'wrong' and the meaning that goes with it do not exist outside of human society. Is it 'wrong' when Poison Ivy gives my dog a rash? Of course not, that's a ridiculous stamement, but neither is it 'right' and that's because morality doesn't apply in that situation. You can only use concepts of morality with human interactions; when we are doing things that affect something else, and if science is to be used as a way of 'objectifying' morality, this needs to be recognised.