While I would normally agree, look at it from his perspective. Say they keep CJ against his will and then they lose. The whole team, players, coaches, gm, ownership, will have this thorn stuck in their throat in the form of CJ letting them all know what they can see for themselves.
If they win without him, then what do they do when the cure-all that is winning brings CJ back? Throw him in at #1 over the guys that go you there? Or have him complaining on the sidelines for the rest of the year? We all know what Al Davis would do, and that's even more proof that the Bengals should just cut their losses and get what they can for him. Hell they could probably get Dorsey for him when you think about it. CJ + the #9 to the Rams for the # 2 and there goes Dorsey to the AFC north. To be honest if we can't get him I'd rather him land there then Atlanta.