cult definition: a system of religious veneration and devotion directed toward a particular figure or object.
The Trumper's devotion to Trump is so strong that it doesn't matter who is opponent is at all. Biden was a irrelevant to right wingers but when he became the guy that took Trump's job then he became the devil incarnate to Trumpers.
The GOP loved Nikki Haley and Ron Desantis but what happened? They are now despised by the right wingers. They are damaged goods because they dared challenge Cheeto Jeebus.
More proof? How about all the people that worked in Trump's cabinet and even his longtime lawyer and fixer? They know him way better than you and I. They were all swell guys on fox news but now they are pure evil because they dare speak the truth about Trump's unfitness to serve. Most all of Trump's legal issues are a result of testimony from Republicans and people around Trump. Yet they are now unbelievable and heretics to Trumpers. They won't even read what they say about him. Apostasy!
Just look at those rallies, with Jan 6th hymn played and arms waved and chants by the crowd and crazy sermons repeated over and over. The same people travel to these things repeatedly.
These are just a few examples of how Trumpism is not a political movement but a cult.