Good question, LTG.  Where do you get truly accurate information on this?  There are a lot of propaganda mills and spinning wheels out there manufacturing "news stories."
On the question of whom we should back  in Syria, there seem to be three choices:
--Assad's brutal, secular, regime,   (Russia's choice)
--ISIS and other Islamic extremists,  
--The diverse collection of "rebels". including Kurdish nationalists, democracy advocates and sectarian militias. 
Of the three, the rebels, whom we support from time to time,  appear  generally closest  to Western values of government, though some  have shown a nasty side as well.  Assad seems to attack the rebels as enthusiastically as he does  ISIS, our common enemy.  
It's a mess which defies solutions,  but with this bombing attack Trump  and  the US are now in it up to our knees. Good luck.