They like that he can do whatever he wants and never see a consequence. They like that he's effectively above the law. They like that he's a pedophile. They like that he openly hates. They like that he's allowed to incite terrorist attacks against anything he feels like. They like that he never apologizes for anything or admits he's wrong. They want to be able to do things like that themselves, so when they see him do it with no risk, it emboldens them. That's his appeal.

The "no risk" is key. These people are cowards. They only act like this when they feel like there's zero chance they might suffer a consequence, when they know they have someone's leg they can run and hide behind. Republican lawmakers have recently enabled this a lot more, and that's why we've seen a huge escalation in death threats, attacks on cities like Springfield, OH, attacks on trans people, etc. If you take away that surety of no risk, you stop them.