You're right that you can't force independent thinking. But you can build cultures that encourage it versus cultures that punish it. Bitcoin culture chose the latter, then acts surprised when it stays small and tribal.
Toxicity is just the first stage of authoritarianism. Right now everyone says "we don't block anyone, it's voluntary". But i'm sure when the masses arrive (if they ever do), most bitcoiners will want to vote out the "wrong" people.
You think smart bitcoiners won't allow capture, but it will come naturally through sheer numbers and social dynamics. The infrastructure might be neutral, but when the culture demands conformity, people will find ways to enforce it. First through social pressure, then through technical gatekeeping, eventually through explicit exclusion.