This doesn't justify Jozu choosing to stand there and is a very poor excuse. Doflamingo is only there to fight against Whitebeard for the World Government, as he's a Shichibukai, and Crocodile has already made it clear he's here to kill Whitebeard. Jozu needs for them to officially declare they're teaming up before he decides they need to be eliminated? I guess that's why he DIDN'T attack Crocodile when he saw an opening. Oh wait..
Think about what you are saying. The Shichibukai who is there to prevent Whitebeard from succeeding is restraining him, and is asking the man who tried to attack Whitebeard to team up with him, and Jozu CHOOSES to NOT resist as his friends engage in war around him, where many of them are dying. THAT makes sense to you? You rather go with THAT over Jozu just being unable to break out?