“Legitimate” tactics from illegitimate bastards

Well, according to Hamas, the official government of the Palestinians strappin’ a bomb to a seventeen-year-old and settin’ him off in a crowded restaurant, killing 9 and wounding at least 60, is a “legitimate tactic” in their war against Israel. Meanwhile, poppin’ a couple terrorist leaders in a car with a Hellfire missile (using a smaller warhead to reduce the risk of killing bystanders) is “terrorism.”
This got me wondering. Have the Palestinians EVER renounced a tactic in their war? Is there ANYTHING they wouldn’t consider doing?
Just what makes tactics “legitimate” or “illegitimate?” What rulebook are they using? Where is this written down?
I’d like someone to explain to me just what is and is not “legitimate” in the Palestinian rulebook. Now, I already know the real answer — “whatever we do is OK, anything Israel does is bad” — but I’m looking for the way these psycho bastards rationalize the way they act. I wanna see just how they justify what they do to themselves and their useful idiots around the world.
Someone, toss a guy a bone.