Obedient human on the leash
People often confuse freedom with disorder, and predictability with trust. Autonomy threatens something psychological that obedience doesn't. Human ability to predict the other person.
People generally build a mental model of someone: "He's this kind of person. She believes these things. He always reacts like this. She's the funny one. He's conservative. She's difficult. He's against this." Once that model exists, interaction becomes cheap. You don't have to encounter the person anymore. You interact with your prediction of them.
And then the person changes.
Not necessarily in some dramatic ideological conversion. They simply stop being consistent enough to fit the character you've assigned them. They praise something they previously criticized. They become interested in something supposedly "not for people like them." They refuse a role they used to perform. They suddenly don't laugh at the same joke. They become less agreeable. They don't fit into the old category anymore.
That creates friction because now the other person has to perceive an actual human being instead of a stable object.
Categorization is incredibly useful for humans because it reduces cognitive effort. "This person is a socialist. This one is a libertarian. This guy loves dogs. Fine. Now the human knows roughly what emotional and intellectual terrain to expect.
But someone who says, essentially, "I think this is beautiful. Tomorrow it's absurd. Six months from now it does not matter. This is much harder to consume. Almost nobody is willing to put effort into this.
You can't easily recruit them into a tribe. You can't reliably predict what they'll endorse. You can't use yesterday's statement as a permanent handle for controlling tomorrow's conversation.
A person who cannot be easily influenced, categorized, guilted, flattered, or socially pressured can feel strangely threatening even when they're completely harmless.
Because influence depends partly on predictability. That's why practically every politician or CEO has predictable behaviour, and their autonomy is well bounded.
If you know which identity a person cares about, which praise he craves, which insult destabilises him, which political tribe he identifies with, which moral label he desperately wants to avoid, then you have handles. Social manipulation becomes much easier.