During last night's debate, Obama had this to say about his PA "elitist" gaffe.

So the problem that we have in our politics, which is fairly
typical, is that you take one person's statement, if it's not properly
phrased, and you just beat it to death. And that's what Senator
Clinton's been doing over the last four days.
And I understand that. That's politics.

Today Obama said that Clinton was "in her element" last night.  Obama likes to claim, and many of his supporters believe, that he only defends himself when it comes to these non-issues he didn't want to address last night.  That he would never go on the attack against a fellow Democrat.

He, of course, is lying.  Remember this?

Barack Obama’s campaign has debuted a new radio ad in Mississippi called "Respect," highlighting what they call “derogatory” remarks Hillary Clinton made about the state late last year.

The ad also argues that Obama will “practice his Christian faith by respecting us” — an apparent push-back against the false Muslim rumors that have dogged him throughout the campaign.

In the 30-second spot, former Mississippi Governor Ray Mabus, an Obama supporter, derides Clinton for comments she made last fall singling out the state’s record of electing female politicians.

"I was shocked when I learned Iowa and Mississippi have never elected a woman governor, senator or member of Congress," Clinton told the Des Moines Register in October. "There has got to be something at work here. How can Iowa be ranked with Mississippi? That's not the quality. That's not the communitarianism, that's not the openness I see in Iowa.'"

Mabus accuses the Clinton campaign of calling Mississippi voters “second class.”

link

Why is it OK for Obama to take people's gaffes and run ads to capitalize on them, but when Clinton does it it's "old politics"? 

Why does he think he doesn't have to answer to the same standards he holds other people to?