We have an ocean to keep the Russians away, it was literally for you all so Stalin didn't pubstomp you all because he got bored.
The U.S. do not look at their national security in such constrained terms.
The United States relies primarily on their territorial integrity, guarded by the US Navy, not the Army.
Canada and Mexico will never be a serious threat for them so they look at the pacific and the atlantic for their territorial integrity. Considering a large-scale conventional threat, the US would not be able to concentrate enough forces to secure both oceans with one navy. This is where Europe comes into play:
The U.S. cannot influence China enough to keep that side of their country safe, but it is also not enough of a problem to be a serious threat as of now. They have allies in Europe, so thats where they focus is.
By stationing troops in Europe, the U.S. can prevent a large-scale naval threat from ever happening (launched from the EU continent).
So no, tits' not subsidizing other countries. That is not how countries work and CERTAINLY not how the U.S. works.
Also considering what I said, WWII can be explained: an eastern threat: japan, and a european threa: Germany.
Thats why they invaded in normandy. not because they loved 'the europhiles' but because they had to.
