Even if it is your right to say that to him, he has the right to a personal opinion to you. With that personal opinion he can do many things.
Not really. Although he has the power, he doesn't have the RIGHT to do all that much. He can get you removed away from him, but not much else. He can say what he wants, but not much else. If he throws someone in jail or hurts them in any way because they told the President he was a giant blistering vagina, then he would be violating that person's Constitutional right to their Freedom of Speech.