I have re-read your posts, and you haven't actually explained anything in detail at all - you are saying (repeatedly) that it is possible to extract information from patterns in the data - subtle patterns, even - which nobody is disagreeing with. Furthermore, nobody is disagreeing that you can pick up useful information from unexpected "side channels" that most people are not really consciously aware of.
But this kind of analysis is not immune to noise. The cleaner and more trustworthy the input data for the analysis is, the more accurate the results will be. Conversely, the more noise you add (including into the "side channels"), the harder the job gets. This is just common sense and I don't understand why the notion is contentious at all.
Your real behaviour is still in there. Everything other than what they're comparing you to was filtered out anyway so adding a tiny bit on top makes no difference. Of course your "noise" is likely blatantly obvious.
Well, you real behaviour - as in your actual purchasing transactions - is something that you cannot really hide. This data has been used for advertising purposes for years.
E.g. see:
https://www.businessinsider.com/credit-cards-sell-purchase-data-to-advertisers-2013-4But what we are talking about here is ads that follow you around depending on what you have recently searched for - at least, that's what I thought we were talking about! :-)
I have noticed that searching for stuff while logged in on eBay means Google ads will follow you around from then on. So eBay is obviously passing data on to Google, based on your account ID. The ads are completely based on what you searched for on eBay. There isn't much intelligence involved, it seems.
Data is also passed from Google to Facebook, and vice versa. I have proven that by using 100% isolated browsers, where a search on eBay in browser A results in being stalked on Facebook in browser B (on a different computer).
Everyone that has data, is in the business of selling it... it seems. Surveillance capitalism, gotta love it.
What's new with Google/Facebook/eBay etc. is that they are tracking people at the individual level, not anonymizing anything, it would seem.
Of course, we live in a free country, and you can simply choose not to use any modern Internet services, if you don't like it... right?