The article is not talking about recording people on the toilet. It's talking about the surveillance cameras that are placed outside, in public. There is no conceivable way for your actions outdoors, in public, to be private because they are taking place in public.

The article also seems to presume that there is some single source where the data from all these disparate systems is tied together, but no such thing exists afaik.

You know what "the map is not the territory" means, right? That one should not make a confusion between reality and (any form of) bureacracy. Now, technically any interaction a real person has on the net is influenced by the map of the person, i.e. by the classification of that real individual. The classification does not have to be geographically centralized, it is enough that the tags the real individual is blessed with by algorithms can travel effectively with the individual. This is technically possible and it is the root of the problem. So not that _they_ know, but that my interactions with other people are mediated not by the territory, but by the map. Who owns the map owns the territory, this way.

You can see that this is the problem in many places. One of those places which springs to mind is that, for example, Google argues that they are just like any user of the (infrastructure of the) internet. But whenever two individuals interact via anything Google, the communication goes mediated by Google. In a sense it is centralized, and there is a centralized map, even if physically spread between variously located data centers.

There is a conceivable way for actions outdoors to be private. Just roll back the clock a whopping 3 decades. Maybe nosy old Ethel notices when you leave for work in the morning, but she's not tracking your face's position and emotion across the city. Your location and reading history is not being recorded from your cell phone and logged permanently. Would it bother you to send me your exact GPS coordinates right now, or if I dispatched a drone to follow you around at all times the instant you stepped outside your front door, then post the video feed on the internet?

There are multiple billion-dollar companies whose entire business is tying together data from all these disparate systems, e.g. Palantir. There are leaked multiple government programs whose entire purpose is the same, e.g. XKeyscore. Or look at something more general purpose like Splunk, where it is trivial to filter 1TB of logs from different sources and map identifiers.