IIRC, Robert Oppenheimer actually DID pass atomic secrets to the Russians, so the revocation of his security clearance and his summons to testify before the HUAAC was hardly unreasonable. He was not subjected to any actual legal penalties as far as I remember. This is in sharp contrast to what happened to people suspected of far less serious activities during Wilson's Red Scare: there were arrests, beatings, prison sentences and deportations, all under the color of Federal authority.