At the extremes:Who decides if you are a really nasty, dangerous person?
Robespierre.
Lenin
Adolf.
Mao.
Pol Pot.
(Dictators of both Left and Right.)
In the USA today there are definitely those in the MAGA movement who are making their own lists of people to be purged in anticipation of a Trump victory and probably some on the far left who'd do the same if they got the chance. Of the two it's the former prospect that's more likely to succeed.