The problem is the National Lawyers Guild was a notorious Communist front. If you have any doubt, this line in their Wikipedia entry is utterly damning:

"Following the Nazis' invasion of the Soviet Union, the Guild gave its support to President Roosevelt's wartime policies, including that of Japanese American internment."

Would people say the same if Ficher's "youthful indiscretion" if he'd worked for a Nazi front after, say, Kristallnacht? (See the above quote, they wouldn't have between 23 August 1939 and 22 June 1941.) Was it that difficult for Ficher avoid working for a cause dedicated to the violent overthrow of the US government and the liquidation of its "capitalist" classes including the wealthier farmers?

Exactly. "I'm not interesting" as a statement of safety has to mean: "I'm going to be very careful to spend the rest of my life not being interesting, and to make sure my family doesn't become interesting either." Otherwise it's just being an ostrich.

Of course, that's one of the aims of a surveillance state: if any word or action could be used against you, then people mainly police themselves.