I don't think it's a strawman. When you corner a theist on this point, she will often claim that god provides objective morality regardless of the existence of hell (or other punishments). They really are claiming that without God, morality disappears--hence the relativists can't justify anything schtick. And hence the standard non-answer to the Euthyphro dilemma, as opposed to simply admitting, "Yes, it's above him but he enforces it."
Philosophy is notorious for not answering the questions it tackles. Plato posed most of the central questions more than two millennia ago, and philosophers still haven't come to much consensus about them. Or at least, whenever philosophical questions begin to admit of answers, we start calling them scientific questions. (Astronomy, physics, chemistry, biology, and psychology all began as branches of philosophy.)
A common attitude on Less Wrong is "Too slow! Solve the problem and move on." The free will sequence argues that the free will problem has been solved.
I, for one, am bold enough to claim that some philosophical problems have been solved. Here they are: