Shia is on my top five favorite actors list. He has a little temper, and he needs anger management, but he's got presence and charisma, or we wouldn't be discussing him. People are so divided about Trump, and both sides pro and con take their stand to fisticuffs. People act and react very passionately about their political beliefs, don't they??
However, he is not a disgrace to Hollywood. Actors have used their fame to make political statements, and/or give their candidate the star approval since the 70's. Marlon Brando refused his Oscar for The Godfather to call attention to the portrayal of Native Americans in movies: always as savages. Do you know that he strangled a cat to death to prepare for that role? That's a disgrace. That's abhorrent.
Actors will always call attention to themselves; they're hard-wired for it.