Hahaha, who's the jerk who offered to buy it? Are you talking about Khedrin Gonzalez?
I understand why it would be pretty crappy, but Illfonic is a small company and purchasing an existing IP for your first serious project is kind of a safe and good way to go. As far as promises back to the community, that's kind of dumb, they shouldn't have done anything like that which they couldn't back up.
Maybe I'll check out Xonotic.