The left is upset because it believes that Obama has not enuncuiated a valid reason for the United States to attack Syria (and they are right).
The right is upset because by backtracking and by denying he ever said that there was a red line that could be crossed, not only is Obama giving Assad a chance to hide the chemical weapons (which they are) but he's making the US look foolish in the process.
Obama should just admit that he's way over his head on the Syria matter and that he really doesn't know what to do now that he's talked out of both sides of his mouth and his ass. Let him hit the links and allow someone else to run things until all of this blows over. I don't know who that would be, but at this point, I would trust John Kerry's judgment over Obama's.