Maybe it's because they had decided years ago there wasn't enough cause to try him, and he's in Dutch now because Mueller wanted a scalp. It's political, and people take the predictable political stance.
Manafort's own daughters said the man had no moral compass. Their text messages detailing their father's behavior reveal levels of subhuman depravity that defy belief.
I know that he's no "OBastard" though, but he's still a loathsome dude.