The FBI (and other agencies) think that by "outsourcing" what would otherwise be a "warrantless" search if they (the FBI / LEO) performed said data collection, it some how absolves themselves of any 4th amendment violations.
It doesn't matter who collects the data, if you are searching through said data, it is a defacto search and gains 4th amendment protections. A third party cannot wave someone else's 4th amendment rights.