Actually, I can tell you that you're probably right. Some of the absolutely mind-numbingly useless data collection in any program is handed to entry-level folks who are eager to show that they can collate and present the data in some interesting way to justify the money spent on the entire program. One of the first jobs most new FBI special agents have, for example, is conducting background checks of current applicants - researching all their acquaintances, tracking down former associates (e.g. first year college roommate and from there any old pals), trying to figure out any weak spots, developing lists of questions and generating reports. I would be frankly very surprised if there weren't several agents whose jobs are 24/7 dedicated to trying to find "subversive or criminal material" on 4chan and Reddit and generate further investigative "leads" for several more agents to follow up on.
The idea is that everyone is dirty to some degree, and the investigative process is supposed to expose anything usable for a particular purpose - whether that purpose is a hiring decision, justifying a prosecution, or obtaining a warrant.
The only way to change it is to massively de-fund agencies that are commonly believed to be acting in the "national interest," in the hopes that they will use their resources on "real" criminal investigations. Since 2001, good luck with that.