Yakov's motive to publically slam Crey didn't sit well with him. Though there were other reasons too because of which he was forced to act a little harshly against him.
First and foremost, he needed to set an example for others. Killing a chicken to deter monkeys, was somewhat of the same situation. Because of his passive attitude, more and more people will see him as weak and would try to step upon him. So to save himself from future troubles, he had to be strict this time.
Also, Crey got a personal call from Butler who threatened him to do something against General's undeserved declining reputation. And this situation had arisen because of rumors of his unjustified entry into merit ranks and his refusal to smash those rumors. Thus, all in all, this was kind of embarrassing for Crey to hear this from the old butler, which in turn made him angry against Yakov.
