In Warren Buffet's explanation he uses selling farm land as this exact example.
Of course under free trade we would expect foreign buyers to own bits of land. The challenge for America: these are not land swaps. America is not buying up bits of land elsewhere. Instead America is selling these bits of land for trinkets.
The US Dollar is a global reserve currency. Which in the abstract sounds nice to have other countries sell US things in exchange for more US debt: but in practice that means selling assets. US Government Bonds or US Farm Land. Both are assets openly traded.
The issue is not foreigners. The issue is America is running up a debt and is selling the farm.