It was to feed his own ego and to continue to feed his followers more of his Trumpicities which they take as law. I suspect that he uses it to boost his support from his followers. He has used this method all of his professional career but because his actions and words can come back to bite him, he is digging himself deeper. He is no longer in the real estate world, he is now in the spotlight for all the world to see. And much to our country's embarrassment.