Ok...
You are in the domain business, not the ethics business,, correct ?
Your name fits perfect for a site masked to "help" students with a degree - it was just a tip of potential buyers - I think these are it (and willing to pay way more than some out of work college teacher having idealistic motives to help people with degrees)
I do not think setting criteria for future use of domain name is a good idea - If they want to use it for wartoys -go ahead and sell it! You are responsible for the name, not the content of future websites. But if you want less for it, go ahead