Political conflict comes from conflicts over facts and values. Facts are relatively easy to establish. Values simply conflict.

Not only that -- there are also models (which, for the purposes of this thread, we can define as maps that produce forecasts).

To reuse the example in the grandfather post, Alice and Bob arguing about nuclear power could have exactly the same values and agree about the facts. However Alice has a model which forecasts that in a hundred years nuclear power leads to radioactive deserts and Bob has a model which forecasts that in a hundred years nuclear power leads to nothing but some safely hidden away containers with radioactive waste.

Alice and Bob differ in their expectations of the future -- that's neither facts nor values.

(Yes, I'm familiar with the Aumann's Theorem, but it just doesn't work in reality)

where they mistake their preferences for facts of the universe

Yes, I agree it's really hard to talk to people who don't realize this.