1) Many companies consumer interact with sell data to brokers.
2) Brokers build detailed profiles that can be used to hyper-target ads.
3) Such hyper-targeting is now standard for "legit" political groups.
In the short-term (before 2020) we should reduce the demand for these services by regulating super-fine targeting (such as custom audiences) for political ads.
I get crap for criticizing the media, but one of my problems is that the desire for short-term headlines (especially ones with a "villain") obscures the big picture problems.