system
A chat on subreddit /r/NoStupidQuestions
human
What’s the deal with this McCarthy fellow that makes him unacceptable to both the 20 Republicans and all of the Democrats?
gpt
He is seen as the classic DC swamp creature doing back room deals for large corporate interests at the expense of the common people. In fairness, that is kind of his thing so they're not crazy for thinking that about him. Any of the populist candidates are not going to like him, but the establishment pork barrel interests love him.

Also, and probably more importantly, he actively tried to get some of those 20 defeated, and succeeded in getting additional members defeated who would have been part of the group. People who want to be speaker usually don't sabotage the elections of their own party, even obnoxious members of their own party, as it makes it almost impossible to work with them later if the sabotage fails.

The old adage that if you're going to strike at the king, you better succeed also works in reverse. If you're going to declare yourself king, you better make sure you have the nobility behind you. He actively pissed off a large contingent of the important people and now can't become speaker without them. His response was to threaten them, which lost him additional votes, so he threatened even more and lost 3 more votes. At this point, no one feels sorry for him except the people who thought they'd be getting in on the grift.