It's like comparing the Japanese American Interment Camps to Auschwitz.
Talk to the countless East Germans who were imprisoned b/c of a tip from one of the thousands of Stasi informants. See if their stories in any way compare to the people who were swept up in the red scare.
I am not suggesting the two are the same, but rather that thinking about the two at the same time and deciding in what ways they are the same and in what ways they are different is a useful exercise.
You can't argue from a position that says "surveillance" and "arrest" are the same thing. They are simply not the same thing. The police cannot arrest you at will. An arrest is a big deal.