Why Is Syria Hell on Earth? Here’s The Ugly but True Answer…
Zaron Burnett III

Nice, yet imperfect.
 You can see now how allying with communists brought it all in an even worse condition. 
America understood, especially with Trump the viscious role of the opposition. They are not much of an option. Right now the adventurism of Obama is checked by Republicans in Congress as well as in the White House.

The only option is putting pressure on Assad without letting the rebels fully winning while having Iraq recapture Raqqa, Mosul and maybe somehow figure an answer with Kurds. You forgot about them of course. The people hated by Turks yet allies with the US.

Geopolitics is merciless. But the US does everything it can goddamit. And that means that good people have to be let to die sometimes. This is an imperfect world. But the alternative of non implication of Americans is far worse. 
You can see that with the lazy whining of Germans and French over the refugees and Syria.