You were?  It's been quite a while since I've been there, but I was always surprised to see the presence of hammer and sickle emblems people had never bothered to remove.  

Well, firstly, Victory Day (the occasion on which these tanks were paraded about) celebrates the Soviet defeat of the Nazis.  

Secondly, there have been some official attempts to integrate Russia's history, the Tsarist, Soviet and current regimes, to arrive at a collective Russian identity.  As with the national anthem.  Which is one of the reasons Putin was chided - promoting the idea that the USSR might be a valid chapter in their history.  

Overall, I think the West is more prone to compartmentalizing Russian history than Russians are.  

"Pretending that you already know the answer when you don't is not actually very helpful." ~Migeru.