Because he was asked a stupid question?
"My client affirms his innocence" is a typical formulation. But he was asked if CB admitted guilt. You simply never have that conversation, unless the client is pleading guilty.
In my bar training we learned never to have a discussion with the client about guilt because if the client says he is guilty, but wants to plead not guilty, you can no longer represent him.
Personally I don't see it as a stupid question. He was asked whether his client tells him that he had nothing to do with MM's disappearance. That's not the same as murder, which is the charge they are pressing for. FF spoke about suspecting HB being the key witness well before anything was mentioned about him in the media, how did he know about that? I suspect because CB told him.
Let me ask you a question, if your client was in CBs position and you were aware of an apparent confession he had made, would you not ask him about it? In order to prepare a defence you would surely want to know what he may have said and to whom, correct? Assuming FF has had that conversation with CB, it would make no sense for CB to deny all knowledge if he knows damn well he has said something to someone.
Of course, we don't know what CB will have told FF about it. He might claim it was just a joke. But then, HCW and BKA have spoke of him saying something only the abductor could know. And there's the possibility of a video in existence, which if true, CB would know about. He may therefore have admitted to some knoweldge or involvement of the abduction but not of the murder. It may be that if police do proceed with a charge, he and FF plan deny the murder but admit to a lesser charge to do with her abduction. We just don't know at this stage.
Also, don't forget, his original lawyers prior to FF quit with no real explanation as to why. It could well be to do with what you say and that during their conversations with CB it became clear he was in fact guilty and that's why they could no loger represent him if he planned to deny it anyway. In any case, being in the law profession, I'm sure you are more than aware of how unscrupulous many lawyers are and they would not care about knowing their client is guilty but plans to plead not guilty.
I just found it odd that he has been asked the same question before and given an emphatic answer that CB denies all involvement. He could have easily repeated that (just like HCW has done on the video question) but instead he paused for a very long time, then chose a carefully worded answer that deliberately avoided saying whether CB denies
any involvement in the disappearance.