If you think only Soviet body builders were juicing, you are sorely mistaken. FYI I am the furthest thing from an ideological defender of the Soviet system as you will find. I am just stating some truths.
Why is that relevant to the discussion? The GP doesn't even mention anything about others. You are the one saying, literally, "Soviet body builders only used free weights and a pull-up bar. You don’t need anything but that to get big muscles." which is patently false (when we talk about "body builder level" big) and then you get defensive when you are called out on it?
I think it really depends on the time period. During the beginning of decline (past 70s until collapse) very few people really believed in Soviet ideologies and corruption was pretty much at the core of soviet lifestyle.
Though before that I could definitely see any sort of doping would be very un-Soviet.
You may also need steroids, which Soviet body builders definitely used.