Fyodor Dostoyevsky wrote in the Grand Inquisitor scene of Brothers Karamazov:

“If God does not exist, everything is permitted."

Of course, even if every action is morally equivalent does not mean that every action has an equal result. There is cause and effect, as capricious, fickle, uncertain, and inconsistent as it may be in many cases. You may be morally permitted to dance in front of a hungry tiger, but that doesn't mean one won't receive a nasty life-ending result.