Your point is well taken but I think Trump’s outsized personality, bluntness (certainly not a Republican trait), his notable accomplishments and ability to conduct huge rallies is perceived as very threatening to the Dems. I think he is somewhat unique in that he launched a powerful movement similar to the Tea Party. Trump is also a person who commands attention.
Bush and all the other clowns the GOP that run for high office simply aren’t in Trump’s league IMO.
That is fine from your point of view.
The left does not see any difference between Trump or Bush.
Look at how they hated Romney and McCain (until they blocked Trump).
My point is that their hatred is stoked every time, regardless of who is the candidate. Trump is just the last one that they were told to hate.