“I’m not convinced the Russians wouldn’t hit ANY “rebel” force in those areas.”
I agree with your hypothesis, but if you look at the Syria Control maps, the “moderate rebels” are the ones holding/blocking the Damascus supply route.
That's why they're dead meat.
And, Obama/Kerry/Carter know that shortly the full extent of their secret little war is going to be exposed.
CIA and Special Forces on the ground. The introduction of sophisticated weapons. Logistics trains.
With the objective, not of fighting ISIS, but of toppling Assad...outside US Law.
That's why they're scrambling to cut a deal with the Russians...in the political sphere.