There are a few reasons for this as I see it. First it would be impossible to directly intervene against Russia without starting a major global incident and very probably ww3 which wouldn't help anyone. Second with the rise of ISIS it is seeming less and less likely that the Free Syrian Rebels will be able to triumph.
The US doesn't like Assad but they like ISIS much much less and really that seems like a fair call. What the US is doing is arming a few carefully vetted rebel groups. This week the Americans dropped 50 tons of munitions to a rebel group.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.