Kerry's apology consisted in being sorry that his joke was misinterpreted. This is more or less saying that the rest of us are also stupid and should also be stuck in Iraq.
Did you hear his statement the other day? He said he meant to say:
"Do you know where you end up if you don't study, if you aren't smart, if you're intellectually lazy? You end up getting us stuck in a war in Iraq. Just ask President Bush."
So in other words, he is now saying because the troops are stupid they got us stuck in Iraq and Bush knows this. He could have said "Bush is stupid and got us stuck in Iraq" but he didn`t, that`s because he meant the troops, not Bush.