That's almost like saying Newton _borrowed_ his works from unnamed linguists of the past who invented alphabet and writing.
Russians did get a huge boost in rocket tech from von Braun's works. However it was a long way to orbital carriers. After R-1 - a copy of V-2 - USSR made R-2 with better engines (more concentrated ethanol), separatable warhead and load-bearing tanks, then R-5 with even better engines and range, then switched to kerosene engines, practically building technology from scratch (engines, for example, used structure brazen to copper-based heat wall with milled cooling channels), multiple stages (did you see how R-7 does staging? It's a ballet in air), "tulpan" launch system, producing base for still flying Semyorka.
George Sutton, author of "History of Liquid Propellant Rocket Engines" mentiones that USSR spend quite a bit more perfecting engine technology than other countries. That's part of the reason why 26 years after dissolution of USSR the technology created there is practically used with modifications on modern successful launchers (including in USA).
In general, if you have a country with big population, economic and schools producing some Nobel prize-level scientists it's hard to defend the idea that nothing of value can be made there. That doesn't diminish USSR big shortcomings but the credit is certainly due where it is.
Regarding Operation Paperclip - did you read Chertok's memoirs, where he describes his part of the story (he participated in the hunting for specialists in Germany during 1945)?
I have a friend who's into alternative history and conspiracy theories. Our discussions so far come to the point of how hard it is to have an objective criteria for correctness. Right now many people can choose beliefs and afford to stick to them even if they aren't supported by reality - because that doesn't affect them much.
In a way, my answer to your question is "it depends". For somebody with "good enough" criteria of correctness I can provide examples.
Russians did get a huge boost in rocket tech from von Braun's works. However it was a long way to orbital carriers. After R-1 - a copy of V-2 - USSR made R-2 with better engines (more concentrated ethanol), separatable warhead and load-bearing tanks, then R-5 with even better engines and range, then switched to kerosene engines, practically building technology from scratch (engines, for example, used structure brazen to copper-based heat wall with milled cooling channels), multiple stages (did you see how R-7 does staging? It's a ballet in air), "tulpan" launch system, producing base for still flying Semyorka.
George Sutton, author of "History of Liquid Propellant Rocket Engines" mentiones that USSR spend quite a bit more perfecting engine technology than other countries. That's part of the reason why 26 years after dissolution of USSR the technology created there is practically used with modifications on modern successful launchers (including in USA).
In general, if you have a country with big population, economic and schools producing some Nobel prize-level scientists it's hard to defend the idea that nothing of value can be made there. That doesn't diminish USSR big shortcomings but the credit is certainly due where it is.
Regarding Operation Paperclip - did you read Chertok's memoirs, where he describes his part of the story (he participated in the hunting for specialists in Germany during 1945)?