Kuzan is a pretty disgusting person if he is fine with his former friends potentially getting killed, regardless of his "own way" philosophy. He is also pretty foolish to get tricked by Blackbeard to overlook all consequences (and after all Blackbeard's own masterplan) so easily.
One can also compare this to his objection to Sakazuki, it doesn't seem like he made a consistent trade-off. I half wonder if Oda even thought about it completely. But there is potential for Kuzan to either have a plan in the backhand or to develop officially into a dirtbag.
I suppose we have to give him the credit of the doubt for the former option...