In one, the invaders are good; in the other, bad.
In one, hospitals are only bombed when they serve evil; in the other, hospitals are always good.
In one, the bad guys prevent civilians from leaving; in the other, the good guys only have civilians at heart, at least when they're losing.
The picture blurs because I have no doubt that Assad's not nearly as concerned as many of the US forces are--the Iraqi forces, on the other hand, are a different story. The Shi'ite militias, Kurdish forces, and Iraqi army have no great love for the Sunnis, and there's rather less appreciation and concern for life (at least the life of those that aren't their own) than others might.
Quickest way to get help for the civilians is to end the siege. Either let the "rebels" win or defeat them. It's the status quo that's bad, but the rebels' defeat is seen as worse. Civilians now under Assad's control in E. Aleppo are being removed from the rubble or, in some cases, have vanished. The assumption is that the young men that have vanished are considered opponents; I'm sure this is the case in some instances, but not in others. We'll see--most of the reporting is simple fear, suspicion, and ill-will. (Which is at the heart of all fake news that we so claim we dislike.)