Probably just bad luck. TSA seems to have designated targets for abuse. My wife is one of them. Every time we travel, she consistently gets selected for secondary screening while I breeze on through. There is not a single thing about her which even a fanatically committed conspiracy theorist could spin as a justification, but it has been going on for years. She has a good sense of humor and the agents treat her well enough, but having your stuff rummaged through every time you go through security is grating.
Even paying for PreCheck doesn't get her off the hook. You'd think it would help, but no.