Wow, this is just sad. Did the developers not realize this was in the agreement when they got the machines, or did nobody read the that part? Nobody put a gun to their heads and forced them to rent the machines.
Seriously, how entitled to think they should get all the money back! The fact that Apple was going to give them $200 when the contract finished was generous enough. It's kind of obvious Apple would want them back, so they don't have to provide software support long term.