My housemate is not careful with their digital privacy so their devices are all unambiguously theirs and the profile assembled by advertisers is likely cohesive

My housemate is not careful with their digital privacy so their devices are all unambiguously theirs and the profile assembled by advertisers is likely cohesive across platforms. Two days ago they said they've been getting a lot more ads about prescription vaginal creams lately. This wasn't happening a week ago. There is reason to expect that someone with access to their medical history would segment them as a likely target for such ads. The topic hasn't come up in their life recently so it would have had to have been from medical records. To be perfectly clear: this probably wouldn't be happening if Google was telling the truth about not using the data for ads. It's time to stop believing ad networks when they say they're "not going to use this data for ads" and "are doing everything they can to keep the data safe". Singular anecdatum, I know, but if we find enough examples of similar occurrences we may be able to build a strong case that they're simply lying about the security of our data in their hands.