I think it's based on over-simplistic-false (oversimplified to the point of being false) social theory that the wheels of history always move by the rare traits of a few people.
Now don't get me wrong, sometimes that is exactly what happens; but not all the time and there are categories where that is generally not true.
A think a repressive government is one of those categories.
Let's take Napoleon Bonaparte vs Adolf Hitler for example.
You kill Napoleon you change history, no doubt about that (in my mind) because Napoleon Bonaparte was a military genius who lucked out and was given an army in a time and place when winning battles could get you a country.
But would killing Napoleon make the french revolution any less bloody (Yes I know he was after the reign of terror), but suppose he kept it going? No it wouldn't end there. Just as there wasn't any one particular person you could kill to prevent it from happening.
History assigns a central role in all cases, in this case to Robespierre, but I believe Robespierre was 'surfing a wave' and not making a wake.
So was Napoleon in the social science sense. There was a thousand ways Napoleon could dominate his enemies on the campaign trail but there was really only a couple ways he could sell a narrative to the people of France and Europe.
Eisenstein was a remarkable man, but killing him would not have prevented the war which found a use for the atom bomb.
Adolf Hitler was not a remarkable man, or rather I should say his skills were not very unique. He was a brute with good rhetorical skills, there were hundreds like him, it was dumb luck that he ended up the fuhrer.
Trump is the same (morals aside of course).
These men and women ride the wave of history, and at the risk of mocking my own theory I'll use a sci-fi term: riding the flow of pyschohistory.
You kill one suffer, there are thousands more who will do the job. You take them out of politics, there are thousands more. Yes people convince themselves it's all about one man and his unique evil, but I think they're wrong.
If this system is implemented, I think it would prove it. There aren't enough prisons to hold all the people willing to go to prison to stop the next Hitler when they are so easily convinced the next Hitler is in front of them. Parties don't have enough candidates to field.
It would keep going until tens of thousands of people are in prison and tens of thousands of candidates are excluded and in the end nothing would have changed. The AFD would still exist. MAGA would still exist.
In fact what this would ultimately do is make sure the puppet masters never put themselves in the firing line by running for office.