"Jokes" are acceptable when they are hugely offensive to many, many people? How does that work? Sexual harassment is "just banter" now is it?
He's an idiot, I agree, but he is also a world leader, and deliberately doing something that many people would find grossly offensive, like tweeting yourself dressed as the Pope, or turning a war torn country where people are dying daily into a holiday resort are not jokes - they are the worst of offensive bad taste.