I understand that the parent's point is "people who are into fishing and baby wipes" is not a coherent or meaningful group (in the sense of 'stratum' or 'cohort

I understand that the parent's point is "people who are into fishing and baby wipes" is not a coherent or meaningful group (in the sense of 'stratum' or 'cohort') of the population. Neither fishing nor baby wipe marketeers would typically care about this so-called group. If you are really applying attribute tags to individuals, you are not "grouping" them in the usually-understood meaning of stratifying. In truth, you are still building an individual profile for each person, but describing it in a disingenuous way.