Are the State Department and Secretary Kerry neophytes? Arming the rebels in Syria is simply not in the best interest of the United States.
Sure President Bashar Assad is a dictator, but what do we think the rulers of Saudi Arabia and Qatar are? Moreover, the dictators there are the ones who are funding rebels who want to establish sharia law in Syria and beyond.
Assad is not an angel. However, any successor who arises from the rebels now fighting him would be much worse for us.
Trying to differentiate between good and bad rebels in Syria, when they routinely coordinate and cooperate, is foolhardy. And from the perspective of the United States, none of them is a better alternative than the current rulers of Syria. In some rebel-held territory, they are crucifying people and forcing Christians to pay a special tax not to be killed. Where do we think the equipment we are providing the rebels is being used? When are we going to learn?