Back in the old days, explaining that George Bush sucked was actually a valuable contribution to the discourse as it was a weirdly lacking perspective in the media. 9/11 and war justified everything and it was conventional wisdom that "the adults were in charge" after all that nasty Clinton business.
I don't need to try to explain why Trump is horrible. He makes that rather obvious. Everybody knows this except the 40% who think he's fine and nothing can convince them.