Really recommend the books Controlling People by Patricia Evans and The Verbally Abusive Relationship (same author). It explains fascism at a personal level so well.
Basically, they get a sense of fulfillment when they project and violate boundaries. The control is just them violating boundaries. They will keep amplifying and they will never stop because the fulfillment feeling is so good to them when they project and violate/control and they believe they are entitled to it. The ultimate amplification and control being death, of course.
Normal people show love by respecting boundaries as a celebration of who that person is. You don't like peanuts? Ok, no peanuts, you are a peanut hater and I know, love, and respect that about you. Whereas a controlling person will hear a boundary like that and it bothers them as a separation between them and their projection, so they will do things like sneak peanuts into food or force someone to try different peanut foods. This is often seen as a power struggle, but it is really just a way for the controlling person to feel satisfied over and over again.