That isn't the only industry that can be subject to a NSL. We are lucky to have any of the information at all; if you limit your search to very-specific categories, you risk finding areas that have less public data.
That case has nothing to do with discrediting someone as a terrorist or gang member, charging them with any crime, forcing a confession out of them, and really anything to do with criminal charges or jail time at all.
That isn't the only industry that can be subject to a NSL. We are lucky to have any of the information at all; if you limit your search to very-specific categories, you risk finding areas that have less public data.
I would start here: https://www.aclu.org/cases/doe-v-holder