Congress wanted to hide behind CMS. Let them get their hands dirty.
What will they do now?
Yes, the other side of the oft-repeated "out of control federal bureaucracy" coin is that Congress has been laboring for years now to avoid political accountability, on every issue of real importance, at all costs. This is true of both parties, who have been more than happy to slough off the responsibility to act to the aforementioned "unaccountable" bureaucracy.
GOPers in particular like it because it allows them to then adopt an attitude of outrage (albeit, altogether feigned) and raise yet more campaign cash from the rubes who imagine that electing yet another Republican to Congress is going to change something.