Or, put another way, what can you do?...or at least say?
Is it either/or? Support the Assad regime as a "progressive, Arab Socialist bulwark against US/Israeli imperialism, or support the rebellion and be a puppet of "reactionary forces?"
Whatever the pretensions of the Assad family dictatorship and its Baath party, it is neither progressive, anti-imperalist, nor socialist. It's an ethnically based dictatorship, supported by a business class and military caste. They have maintained power via a police state and mass murder. It rhetorically supports Palestine and denounces Israel while mistreating Palestinian refugees in Syria, keeping the status quo at the border. Israel has relied on the Assads, pere and fils, to maintain stability.
It's easy to see why people would finally rebel. This is a popular uprising. There's no way it could have the energy and momentum it has if it was some artificial creation of the CIA, Mossad, or whatever.
There are diverse forces entering into the fray in Syria. There's no assurance that it will ultimately win (although it look like it at this time) and its unknown what will happen if the revolutionary forces prevail. Don't count on being able to predict it with any assurance. Are there pro-imperialist elements involved? Certainly, the US will try and contaminate and take advantage of any opening it sees. That is a given in any social struggle anywhere in the world. But that's life. Should oppressed people not fight for their rights because reactionary groups and/or countries will try and influence events? Ideological perfection and complete clarity has never been one of the strong points of real life in this world.
To oppose the uprising and give support to Assad is both shameful and stupid.