Either you support unlimited immigration or you are a racist.
Either you are 100% on board with the entire vaccine schedule or you are an anti-vaxxer.
Either you say that Covid was a natural occurrence or you are a conspiracy theorist (and probably a racist too).
And so on.
Say what one will, but it's effective.
I think one reason it works so well in the US is our puritan heritage, which has always had a strong manichean current in it. As the elites lost their religion, they retained this characteristic and it now manifests itself in the secular realm.