It was the other way around. Dick had constant harping claims that Lem was a communist committee invention as it says in the article that you linked.
> Lem, however, considered one science fiction author as exempt from his scathing criticisms – his denouncer, Philip K. Dick. The title of an essay Lem published about Dick is evidence enough of this high regard: A Visionary Among the Charlatans. The essay itself waxes lyrical on Dick’s many excellent qualities as a writer, and expounds upon the dire state of US sci-fi. Lem considered Dick to be the only writer exempt from his cynical view of American SF.