So... why is the government treating this guy like a monster again?
To be realistic about this, Manafort has always been dirty. The whole Manafort/Atwater/Stone partnership used to be the face of corrupt, lobbyist driven, do anything to win, politics. Often the right likes to overlook their own slime to keep their voters focused on the slime on the left (and vice versa).
People think there is one 'swamp' and it is them versus us, but in reality, there have always been multiple swamps fighting each other. And the stakes have always been huge.
For control of the Republican Party, it generally has been a fight between the DC Powerbrokers and the NYC Money Establishment (especially from the 60s-80s). The latter was considered the most corrupt in the party and was pretty much run by the Manafort/Atwater/Stone partnership.
Much of this changed in the 90s with the boom of the 'Christian Coalition' with Pat Robertson rallying what we would call the unrepresented, and the NYC Establishment saw this and cozied up to this group as they saw power in numbers. They helped frame it as 'us versus them' but they were always part of 'them'.
But the game really never changed. There are many, many swamps and many 'establishment' circles all fighting each other.