There were also real Communist agents. See

https://en.wikipedia.org/wiki/Venona_project

https://en.wikipedia.org/wiki/Klaus_Fuchs

https://en.wikipedia.org/wiki/Julius_and_Ethel_Rosenberg

There were also real, devastating consequences to Communist ideology. See

https://en.wikipedia.org/wiki/Holodomor

https://en.wikipedia.org/wiki/Great_Chinese_Famine

https://en.wikipedia.org/wiki/Cambodian_genocide

for three examples.