What is your basis for calling them "witch hunts" rather than "criminal prosecutions"? (The prosecutions would start only after the passage of a new law making the questions and experiments illegal.)

If you work at a defense contractor on warplanes, radar systems or nuclear weapons and you are too free in how you teach or write about your professional knowledge, you go to prison, and it has been that way in the US continuously since WWII. Criminal prosecutions are relatively rare because security-clearance background investigations filter out most of the job applicants who would go on to violate the laws.