Putting aside his other behaviour while President and before (and I realise that's a lot to put aside), he's been utterly irresponsible to create this situation for the President of the United States.
He's been doing his damnedest to catch Covid all year, with his mask-refusal, his continual assembling of close-packed crowds and his refusal to follow precautions. And that's despite the best efforts of staff around him to keep him safe and keep him informed about the risks of Covid.
He's not a medic or care worker, taking risks for the benefit of others. He took very high risks for the hell of it, because he wanted to. He made it inevitable that he would catch Covid sooner or later.
And now the US has a Commander-in-Chief in hospital who may become incapacitated. The Presidency isn't a crown, it's a job, and needs someone fit to do the work. His actions may also have infected many other workers in the West Wing, and in the other branches of government: all down at the same time.
This is an unthinkable level of irresponsibility. He's causing a vacuum at the centre of power.
And at an important time like an election, too. He could be re-elected President in November, and by January be clearly too sick longterm to actually do the job.
If I were a supporter of him politically, I'd still be absolutely furious with him as a person for doing this.
He's put his own selfishness before his duty to his office and to his country.