As someone who brokered Lexis PII in a past life, what scares me about this is how dirty the data are.

That said, it’s not a loophole. State and federal laws make certain data public or quasi-public for limited purposes, and I can’t think of any reason the government should be prohibited from buying it for one of those purposes. The fourth amendment is designed to prevent the government from collecting information that is distinguished as categorically private by definition.