Conservatives have railed for years at similar gaffes, scandals, and culpability being treated differently in the MSM. Can you imagine if Bush had said that, what the uproar would be? Sometimes they even document very close equivalences being trumpeted in one case, buried in another. Now that there's an alternative media, with liberal corners, conservative corners, libertarian corners, and every possble outlook corners, we see that the right-leaning sources do a bit of that when they have the chance as well. I tend to see that more in the comments sections than in the actual essays and posts, but the tendency is there.
When these pitched battles about whether Politician A's comment is in fact better or worse than Politician B's, you can always find one of these cultural buttons, one of the tribal markers I mentioned in the first essay, just beneath the surface. It is not necessarily that people are trying to make one side look bac and the other good (though that certainly happens). Their irrational and emotional responses got called into play by one of those egg-cracking items. Politician A's comment shows that he is not one of us, and we thus perceive it as far more outrageous. If it offends our tribe, well then all Americans should be offended. In fact, if you're not offended, that shows how stupid and morally bankrupt you are.
You may notice that this is how comedians, filmmakers, entertainers, authors, and cartoonists make their living. When you try to pick apart their snark for a logical connection between their insult and reality on the ground, you find that it's not there. It's just ringing people's bells, evoking tribal responses.
Update: Like this poll over at Fox News, which just showed up today. Heck, it doesn't have to be flags. It doesn't matter what you actually say, but if your words can be made to sound racist it's a scandal, because you should have been more careful. But Helen Thomas isn't held to the standard of making absolute double-sure her words can't be misconstrued, because making anti-Israel remarks that could be considered antisemitic is no longer on the tribal out-list for liberals. In fact, some folks think of it as a plus, showing your support for the Palestinians. Both liberals and conservatives might watch the Daily Show, but picking up references from Stewart or Colbert are required for young liberals. Otherwise you might not be seen as a real member of the tribe.