The initial uproar was over some teaching materials to be handed out as a complement to the speech. These materials supposedly called on our nation's school children to don berets and become Marxists or something. I don't know -- not being a teacher I didn't see the materials in question. Let's say the charges are true (I doubt they are, but bear with me): the materials were pulled and never distributed, so our kids are safe.
Today though, I saw a piece (via Instapundit) that reminded me about how Democrats went cuckoo for outrage puffs back in 1991 when then-President George H. W. Bush made an address to schools. Congressional Democrats threw a hissy fit, the Washington Post tut-tutted about propaganda being forced on our kids. There were Congressional hearings and everything.
I get the allure of "but they did it too". It's easy. You get to drag up stupid things the other side did and play the hypocrite card. The problem I have is that it buries the fact that the behavior was wrong in the first place under an avalanche of righteous indignation [*].
When someone yells "but they did it too", what they're really saying is, "it was wrong when your side did it, but it's okay that our side does it now because we're evening the score." What they're really doing is performing an act (or repeating a meme, whatever) that they believe is wrong. It is, at heart, a logic error.
Of course, the same conservatives who complain about Obama now will not have a problem when the next Republican president speaks to the nation's schoolchildren. The same liberals who defend the Obama school speech now will condemn the next Republican administration's address. And the cycle repeats.
It's an amateur argument. Either you believe an act is wrong or you don't. Defending an action on your side, then condemning the other side for the same action using the justification that "they were against it before" is hypocrisy. It doesn't bring anything to the greater debate. All it does is prove you stand for party, not for prinicples.
[*] The best kind of indignation!