Some people claim that there are objective values.
It could not have been wrong by Hitler to systematically murder 6 million Jews if there are no objective values, they say. Therefore, they argue, we should believe in the existence of an objective morality. What they fail to realize is that if there was an objective morality, it could as well have been morally correct by Hitler to do what he did. Those of us who oppose the killing may be wrong, and Hitler may have been right. At least this would be logically possible, while if there are no objective values, it could not have been right for Hitler to do what he did.