The Soviets didn't always cover themselves in glory. Let's not forget the invasion of Finland, annexation of the Baltic states, division of Poland, the Katyn incident and sitting by doing nothing as the Warsaw uprising happened (admittedly Britain and France did eff all when Poland got invaded in Sept 1939, hence the phoney war),
The part of Poland the Soviets took was the part of Russia the Polish seized in their conflict just after WWI... the land the Soviets took was former Russian land stolen from them by Poland. Finland was also part of Russia as were the Baltic states.
Finland had sided with the Germans so the west should have supported the Soviet attack on Finland, Stalin asked for land to improve protection and defence of Leningrad which was in an exposed location... the Fins refused so Stalin attack them and took what they wanted.
The Warsaw Uprising was an uprising by UK supported Polish factions that wanted to seize power ahead of the Soviet troops arriving so they could dictate terms and control Poland... why would the Soviets rush to save them.... just like the US and the UK delaying D Day till 44... let two enemies fight each other and wear each other out...
so it's no surprise that the West didn't always have the best opinion of them.
Have you read the books or seen the TV series Reilly Ace of Spies?
The west was no an ally by choice with the Soviets, they hated them only slightly less than they hated the Nazis... in fact today they try to equate them as being the same... yet pretended to be allies working together at the time.
At a minimum, they were supplying Germany with ball bearings.
They were producing AA gun shells to shoot down American and British bombers... it wasn't just nazi gold and blood diamonds...
This idea of having enemies as friends against communism reminds me of Vietnam. It was rather shameful what happened there after the second world war where Ho Chi Minh and Americans sympathetic to their cause were disregarded due to a rather irrational fear of communism here which led to the allies arming Japanese POWs to fight their old allies, the Viet Minh.
The irony of a people trying to be free and throwing off the shackles of imperialism were bombed by America... a country colonised by european colonial powers of Britain and France and Germany and many other countries... Vietnam is known as a war in the west rather than a place but which war... the first wars to get rid of the French, the war to get rid of the Japanese or when the French came back and then the Americans... if the Ho Chi Min had been supported by the Americans against the French things could have been totally different...
The amusing thing is that some blame communism for the wests antagonism against Russia but the Antagonism existed well before 1917... the British feared the Russians would steal India from them for a very long time and most British colonies feared the Russian menace... load of old poppycock.