It is true that Russians helped in ending WWII but as others pointed they were also one of the initial aggressors and allies of the Reich. If not for that the war might as well end faster.
The war would have ended even faster had Britain and France not let Chechoslovakia get partitioned. They proved themselves completely unreliable, and unsurprisingly, after a failed attempt to turn West, Stalin signed a deal with the devil.
The Molotov-Ribbentrop pact was not signed without context. The USSR sought out, and was rejected from an alliance with Britain and France.
The Molotov-Ribbentrop pact was not signed without context. The USSR sought out, and was rejected from an alliance with Britain and France.