No, but when I read that they used to work for Hostess, they go into the “No Interview” and thus never to be hired pile. I cannot interview every person who applies, so I must weed them somehow. This is just another factor for not getting an interview.
This is, as I understand it, legal. (I am not a lawyer.) You cannot ask about prior union membership or you open yourself up to charges. But you certainly are still allowed to say, “If this person was employed by company X, I do not want them working for me as I view the company as incompetent in their selection of personnel” or other similar declared logic.