(On the "flaws" of moral relativism):

When you get into a discussion with an atheist on this subject, they invariably sneak objective morality into their replies. It is usually pretty obvious when they use phrases like “right” or “wrong” in a clearly objective sense.

When you present the Moral Argument for the existence of God, the atheist will invariably engage in the Atheist Shuffle – bouncing back and forth between denying Premise 1 or Premise 2. It can be quite frustrating.

“So, now you believe in objective morality?”
“No, morality is relative.”
“But, you just said that what Hitler did to the Jews was wrong, objectively wrong, right?”
“Yes.” :-)

What it REALLY comes down to is this: atheists reserve relative morality for their OWN actions while affirming objective morality for the actions of others. Very convenient.