The substance of my case is "this won't work, this provides no value to users, this is disclosing a non-zero number of bits of information about users, and this

The substance of my case is "this won't work, this provides no value to users, this is disclosing a non-zero number of bits of information about users, and this is nothing but attack surface area for potential information disclosure". Once you have a non-zero number of bits flowing from the browser to advertisers, that's a path to try to extract more bits of identifying information than the browser intended to provide, by any number of means. There will be lots of people trying to deanonymize users from the data. There will be warrants served to the intermediary. There will be attempted security breaches on the intermediary. Those are just a few bits of potential attack surface, all of which is entirely unnecessary.