"Yes it was."
No it wasn't - as somebody here said "The Nazis were the natural enemies of the Bolshevics" - Oh, that was you.
Stalin signed a non-aggression pact with Germany and then set about preparing for war with them - anything done between the two on the part of the Soviets was defensive.
This is not to say that the pact was the right thing to do, though I'm not sure what alternative the Soviet Union had in the circumstances - Stalin had ceased to be interested in building a Socialist state, but the idea that the Soviets were allies is a nonsense - as you rightly said, the Soviets and the Bolsheviks were natural enemies.
Russia became an ally of Britain and later, The U.S., when they got round to joining in.
"Rubbish. The Moscow Trials were well-known at the time"
The Moscow Trials were aimed at politicians and were sold as trials of enemies of the Soviet Union - Fascists - exactly how Trotsky and other leaders of the old guard were described (again, so much for the Soviet Union being an ally of Hitler)
The Trails hardly touched the ordinary man in the street, who were fed the propaganda, and fell for it, as did the left and liberal left outside.
Stalin was idolised by the Russian people, even after the 20th congress.
He was, in fact a leader who was in the right place at the right time, pretty much like Churchill who one minute could be shooting down striking miners in South Wales and next, be adored as a wartime leader.