This man is the President-elect of the United States. For him, or any other adult in anything resembling a responsible position, tweeting like this is juvenile beyond words; it is non-productive; it is embarrassing for the rest of us (although many may not find it embarrassing to them); it is an embarrassment for the country.
It is teenage, Butthead and Beavis mentality crap.
Whoever has control of his leash needs to tighten it up. Maybe get him a choke collar and housebreak him.