Only because fascists inevitably eat each other. Nazi fascists and red fascists worked together until one turned on the other.

Say what you want about the US, but they could go right to the Nazi beating without having to cooperate with them first.

And Stalin literally did not kill Hitler. Hitler killed Hitler, in true fascist self-imploding fashion.

Also is someone who thinks that Stalin killed Hilter really qualified to know if a youtube entertainer is a historian.