The reason rulers like Assad become official boogeymen is not because the US cares about human rights all of a sudden, but because they stand between US oil and the neocons. This is what the CIA does, rinse and repeat, over and over and over again. They set countries ablaze, arm violent opposition, watch the people burn, and then go in to play savior.
It wasn't long ago that Assad was the
darling of the west. What changed? Did Bashar Assad just arbitrarily decide to start murdering his own people? What changed- of course, obviously- was the oil politics.