The 14th is a reconstruction amendment btw, it wasn’t drafted or ratified by the founders.

Is this a US thing I’m too French to understand?

I’d say likely yes to this. It’s much easier to centrally govern a more geographically dense and homogeneous country.

In the US we have strong localized government (city/county, state) and the more sweeping Federal government.

And they do submit to central government, that’s exactly what the discussion in this article is about- will the central court decide to strike down their local laws?