>>213714156The French and British leadership weren't fanatical retards like Hitler was. They prioritized which one was the most urgent threat to deal with. Winston Churchill came up with Operation Unthinkable to attack the Soviets but couldn't get enough backing from the other allies so they dropped it.
Once again, the entire Cold War was about dealing with the Soviets and the threat of Communism to try and liberate eastern Europe.
The allies broke treaties out of sheer pragmatism. Hitler broke treaties out of sheer fanaticism. A very stark difference.