I've asked him if I were to kill him and the majority of people said it was okay would that make it right. His reply is that if the majority of people think it's okay then it's right. I think the statement you quoted supposes that the person answering "No" must have a Jewish or Christian moral foundation of Thou Shalt Not Murder. To him there is no "intrinsic right and wrong".
I've come to believe that a person who does not believe in God can't be made to believe there are absolute right and wrongs. If not for God's commandment, what makes murder wrong?
I happen to know that morality is very logical, and doesn't need a supreme being to enforce it. I would know murder was wrong even without the 10 commandments.