Whether anyone likes anything ever done by the ACC before or not, this was a move that fell into their lap and they acted quick on it.
They replace a crappy broke UMD program with a solvent good UofL program. With ND being promised a spot(not that they'll ever take it), you know technically ND has 2 spots, one for them and who they want to bring with them if they have to join, the ACC was stuck at 14 with no away of adding another FB program. UMD bolting gave them that chance.
UofL on the schedule every year is a lot better than UMD.
Let's not forget UofL was also part of the BIG 12 rumors(that whole mythological eastern division) and they got em.
And yes holding UMD to their contract is the right thing to do. What is UMD gonna do ? They play this year and next year under that contract, are they gonna refuse the ACC checks ? Cash the checks and they don't have a leg to stand on in court.