We all know that Donald Trump is thin skinned, and he lashes out at everyone and anyone who criticizes him. So if her were President, what will he do to protesters, or private citizens speaking out against Trump, the president. Don’t you think he would lash out at those people, too?
And once president, his new law and order presidency can easily put down anyone who speaks against him. He can hassle anyone through legal means (that is not hard to do).
So what is happening here is that we would no longer be a free country, and we would no longer have free speech. People would feel afraid to speak against the president. This is what we have in nations run by a dictator. Trump would try his best to run this country as a dictator.
In addition, I don’t believe he is capable of understanding that as president, he would have many, many limits to his power.