This all derives from a desperate hope that politics has not really, truly, been redefined by Trump.
Populism means a political career is something to be held in contempt. These Never Trump types can’t possibly look in the mirror and declare to themselves that they are worthy of contempt. They think they are noble and if only they can erase Trump, then everything will go back to what it was and all these Trump voters will gravitate where they belong, supporting self declared elites.
“Populism” is one of those terms that’s used like “Fascism”, it’s basically used to describe anything a liberal or a RINO disagrees with.