I know they do care, but I don't know why. I'm not even sure they can objectively explain why.
They probably don't care in reality, but when attack by arguments like these they defend themselves because of the obvious irony in them.
1. Most all horrible inhumane acts in human history are connected to some form of religion
2. There is no evidence to support that people who believe in God are acually morally superior than those who arn't
3. This is simply an arugment of 'We are better than You' and is actually quite insulting and anyone would defend themselves in this situation.