I think I'm just disagreeing with the point.
Most people when you boil morality down to it's most basic idea, agree that 'doing harm' is generally wrong in nearly every moral code ever known to man. Now, you can play the '100% completely subjective' game and say "what makes throwing sacks of babies into meat grinders morally wrong, maybe it's morally right!" Of course I generally agree that morality is subjective, but there are some base principals on which the vast, vast majority of humans and moral codes agree.
Otherwise, if your idea is that absolutely anything could be moral or immoral, you can hardly then go on to claim actual morality can come from religion. Because if throwing sacks of babies into meat grinders could be morally right, Islamic morality could be morally wrong, based on your idea that we just can't make any statements whatsoever about right or wrong.
I assume you're using some odd definition of murder that doesn't include all the slaying that Allah commands. That's righteous killing and not murder or something, right?