Because he wants to freece people that mostly work and do productive things for a living, and meanwhile (some) randos come to the US with stacks of cash derived from US foreign aid, from selling copycat goods on amazon, from selling govt offices in their home country, or with wads of cash from straight up corruption / criminal activity... and they get the white glove treatment.

A non-us citizen real estate tax (in the style of NZ) is like the 3rd rail of politics. God forbid anyone daring to mention a ~200% FV tax on any residential property purchase by a non-us citizen.