You can define it as under-building, but that's only one side of the political effect. E.g. the UK net immigration rate has been pretty enormous, and it seems lopsided to call it under-building to have not built homes for a giant number of people coming from their previous homes elsewhere in the world to the UK.

Speaking as the son of an immigrant, married to an immigrant, for the people who can only think tribally, and must assume I am doing the same.