I suspect the more likely scenario is they don't actually care how accurate these nominal categorizations are. The information they're ultimately trying to extract is, given your history, how likely you are to click through a particular ad and engage in the way the advertiser wants (typically buying a product), and I would be surprised if the way they calculate that was human interpretable. In the Facebook incident where they were called out for intentionally targeting ads at young girls who were emotionally vulnerable, Facebook clarified that they were merely pointing out to customers that this data was available to Facebook, and that advertisers couldn't intentionally use it.[0] Of course, the result is the same, the culpability is just laundered through software, and nobody can prove it's happening. The winks and nudges from Facebook to its clients are all just marketing copy, they don't know whether these features are invisibly determined any more than we do. Similarly, your Google labels may be, to our eyes, entirely inaccurate, but the underlying data that populates them is going to be effective all the same.

[0] https://about.fb.com/news/h/comments-on-research-and-ad-targ...

I think its their currently targeted ad demographic or whatever. Its probably a "meaningless" label to humans, but to the computer it makes more sense, he probably watches the same content / googles the same things as some random person who got that label originally, and then anyone else who matched it.