Her words tell exactly what the problem is. To Pelosi and her fellow travelers, Trump is an imposter because he isn't a career politician, didn't ‘pay his dues’, and doesn't act the way all of them act. Further, Trump showed how pathetically untalented people like Pelosi are, and how someone with no political experience can do a much better job than any of them. He is blowing up their stature, and stature is the primary reason elected office is so important to them in the first place.
Trump is the guy watching the game from his payed-for seat in the stands, and who is really disappointed with the way the game is going. So, he walks onto the field from the stands, throws the rest of his hot dog away, tells the team they are playing like bums, and proceeds to throw a no-hitter and hit for the cycle.
Pelosi and her ilk are part of a worldwide cartel - outsiders are not invited.
Trump's not a team player in the worldwide corruption apparatus, so they're trying to make him out to be the corrupt one since he won't join in on or at least give a blind eye to their corruption. So he is corrupt to them and must be denounced and opposed. Ukraine must be a heck of a rice bowl to them since extremes are being taken to hide and protect all sorts machinations in regards to that place.