You are confusing mechanisms and statistical outcomes.

It's a bit like crowd dynamics. Each individual human is sentient, but if you observe a large enough crowd, there is no sign of sentience in its behavior.

People who are actively involved in politics and advocacy, as well as some terminally online people, often end up adopting the views of their peers. Because they are stuck in their bubbles, they don't consider other viewpoints plausible.

But most people are not like that. In most issues, they are exposed to multiple viewpoints they could plausibly adopt. The choices they make are ultimately their own. Of course, if you know the distribution of people's opinions and situations and the messaging they are exposed to, you can try to predict the distribution of choices. But those are still people's individual choices.