Sure, and that would be a legitimately great service.
But, many people do you think are going to go and check the hash beforehand? How many people even know how to check the hash? Admittedly, the type of user who will go through so much effort to run old Flash content probably skews more technical, but the point remains.
The alternative is that Adobe could just leave the downloads links up under a giant "Not Supported Don't Use" banner. I know which option I'd find more responsible.