I guess the United States owns the moon since they got there first and it was uninhabited when they landed and planted their flag first.

I guess you have missed the last 50 years of diplomacy about outer space claims.

Crazy that the tiny island of the UK somehow also has legitimate claim to land on the other side of the globe too and not the mainland nation that the island is closer to and which was then controlled by them when they got independence from the Spanish.

Oh, you mean like Greenland?

Just one slight difference of course, and that's the fact that Argentina didn't control the Falklands at the time.