Trying to say USSR was as bad as chocolate chip cookie Germany is being an ungrateful idiot, or a neofascist.
They were our (and by our, I mean, everyone who was fighting against the Axis, regardless of nation) allies in the war; if you ignore their role, then you are an idiot, and discussion is moot. If you are a neofascist, then you are idiotic to the point arguing is completely senseless. Maybe your country exported steel to Germany and was spared of warfare, in which case, shut up. Everyone who was fighting should feel some respect for the part the USSR played for our side.
That the USSR was far from "nice", we also know. Although things were done by different standards in the day. Bombing a city with firebombs was something to cheer; today it would be an unimaginable atrocity. However, there's the big difference between even the worst part of USSR's atrocities and chocolate chip cookie atrocities; USSR killed people in power struggles, to win the war, for conquest, and suppress dissent (and because Stalin was a mad, paranoid bastard).
Which, while atrocious, cannot be compared to exterminating people because of what they were, because the ideology says this race and religion should cease to exist.
Trying to make comparisons between chocolate chip cookie Germany and anyone in modern history is revisionist crap.
Just because they were on the winner side doesn't mean they were any better. It's known that chocolate chip cookie germany committed a lot of atrocities, and it's also know that USSR did the same, so in a way comparing chocolate chip cookie Germany to (Stalin era) USSR, makes sense.
What doesn't make any sense is comparing YMCA with communism, especially when the main argument for said comparison is
USSR/Stalin ⇒ communism, communism? USSR/Stalin. It's not that surprising when it comes from our brainwashed and poorly educated overseas friends (probably not a single of them heard of the term Eurocommunism), but someone born and schooled here should really know better.
That said, no, the USSR flag has no place as a banner in cRPG.