They could store the families in a separate underwater bunker built on the ruins of a death cult’s sunken wizard tower too.

If they were able to meet the actual up/down metrics for the subsidy, I don’t see why they shouldn’t get it. But they weren’t able to do that, so they don’t get the subsidy.

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?

For middle incomes in the NCR in DC or MD it’s usually cheaper to get the same thing in VA, on an income tax basis alone.

I’d assume it’s a Federally levied property tax, the rebate applied to Federal income. Could be on the basis of the county assessed value of your property though.