My understanding of what you wrote:
The term “Red Scare” is universally used where leftists assert that Communist infiltration was NOT a real problem. Leftists assert that a “Red Scare” was/is propagated and enhanced by people (such as Sen. Joseph McCarthy) for rank political gain.
Did I get that correct? Tx.
Film from the era: Blood Alley, starring John Wayne and Lauren Bacall
https://en.wikipedia.org/wiki/Blood_Alley
Yes. Leftists universally assert that McCarthy used it as a political cudgel for personal gain.
The truth is, our government was riddled with Soviet Agents, and and just to name two specific instances, the loss of China to Mao (by John Service, Solomon Adler, and Chi Chao-ting (all Soviet agents) and the betrayal of the Yugoslav fighters under Mihailovic in favor of the communist Tito (accomplished by Soviet Agents working for the British Government as the “experts” on site in Yugoslavia were BOTH minutely orchestrated by Communist agents.
They were Soviet agents in positions of supreme influence in both China and Yugoslavia as the recognized experts of what was going on, and they sent steady streams of correspondence to people high up in their respective governments who trusted them and those correspondences portrayed Chiang Kai-shek and his government as corrupt, and collaborators with the Japanese, and Mihailovic in EXACTLY the same way, and suggested we should dump them in favor of Mao and Tito.