“NATO existed so that the U.S. military could start fighting the Warsaw Pact at the inter-German border”
Interesting. NATO was formed in 1949. The Warsaw Pact was formed in 1955 when West Germany was allowed to remilitarize and join NATO.
In 1949 the Russians were occupying East Germany with no intention of letting it go. Same goes for all the other countries that the Russians later formalized control over in the nonconcensual Warsaw Pact. The Russians were an occupying force when NATO was created. Giving it a cute name later didn’t change anything.
The Warsaw pact was in defacto existence the summer of 1945. Stalin had no intention of giving anything up.