Would you have known how truly evil some of these people were if he didn't shove them under the spotlight for all the world to see? No.
It has been said that Trump was never "bankrupt." Instead, at one point in time, he needed to know who was genuinely loyal in his circle, so he said he had no money. He was surprised at the results. Some he thought would be loyal were not loyal. Some he thought would not be loyal were loyal. This is not his first game of "cat and mouse." He knows how this has to be played.
Two reasons: