The previous administration may not have been the absolute worst in our history, but was surely in the bottom five of all time. The combination of incompetence and policies antithetical to our own interests didn't make it a difficult decision whatsoever. Whereas you and others speak of vague, nebulous concepts of "America's standing in the world," critics of the last administration could point to real, tangible harm done by its incompetence and weird philosophies that regard our country and our people as oppressors of different sorts. Biden wasn't running the country, so the people around him ran it, and they were people who are now common on the Left who hate their own country. Listen to Joe Manchin, a Democrat, talk about the people who were around Biden. No country can prosper or even survive long-term when its leaders hate their own country and the common people of that nation. How could you or anyone not pick up on the fact that most of the Left despises the traditional values and institutions of our country and especially despises the unwashed masses, who always seem opposed to fashionable ideas of the washed few?
Your estimation of the moral character of our elected officials is surely higher than mine, as is your estimation of human beings, in general. We are fallen creatures, and so I am rarely disappointed in people, least of all public figures.
I would also propose that human beings are far more able to compartmentalize their lives than you estimate. I have known guys who have messy personal lives which aren't particularly virtuous, yet in business or on their jobs, they are perfectly ethical. I don't think Trump is perfectly ethical on the job, not by a long shot, but given what we saw most recently, from the Justice Department, to DHS, and beyond, picking apart Trump and not the unelected cabal running our country for four years, it rings hollow.