Whats the problem? I have a feeling there is more to it then that. But flying to CUN at 25,000 ft with good weather and no icing with a bleed MEL'd seems perfectly reasonable to me? Unless theres a safety of flight issue, why would you turn that down? Turbo prop guys do that stuff all the time!
I wouldn't take that airplane, either, at least not without some pretty substantial information-gathering.
1) Are you legal to launch ETOPS with that bleed wired shut?
2) What if you lose your other bleed source? If you had to descend to 17,000 feet (APU limitation) would you still have safe/legal fuel reserves?
3) What was your alternate, and what is the MEA to get there? Will you have enough fuel to do it at 17,000 (or 16,000)? What if the APU isn't maintaining the cabin altitude, and you have to descend further? There are serious issues to consider, and it would probably be quicker to get me another aircraft than it would be to gather all of the information I would need to make an informed decision as PIC.
The problem, GT1900, is that you don't really know ALL of the circumstances of why another pilot who refused the equipment. You THINK you know, but all you REALLY know is Management's side of things.
Have you bothered to contact any of these pilots, and asked for their side of the story? Of course you haven't, or you wouldn't have come on here parroting management's positions on these matters.
Have a little respect for your fellow pilots, and if you can't be bothered to seek out both sides of what happened, then kindly refrain from posting misinformation and half-truths.