Why should I? No one can explain how that point of view makes me prejudiced so why should I move on to any other subject until someone explains. No one can show proof of moral equality between Atheists and Theists either. But I have countered, critcized and exposed Atheists on this forum already. Funny how you and others here dodge my questions.
That's because your question starts with a false premise.
You are starting your line of questioning with the assumption that they didn't start out equal in morality to begin with. We are all born neither theists nor atheists, we are all assumed to be born with the same morality. It is only later in life that we chose where our spirituality will lie, if at all. If you want to argue that one subset is different than the other, then you need to show that to be the truth. It's not the other way around. I would view theists or atheists as morally equivalent until proven otherwise.
And even then it will be nothing more than a percentage because I can guarantee you that I am more moral than some theists...