This is actually the most technically correct answer on this page. Everyone is going by their own opinions about definitions of what constitutes human subjects research, rather than starting from the primary sources. IRB guidelines are dictated by the federal government "common rule", a common standard adopted by all institutions that receive federal funding.
"about whom" is a key criteria from the federal government to determine whether something fits the definition of human subjects research. Here's a quote from HHS:
"The phrase ‘about whom’ is important. A human subject is the person that the information is about, not necessarily the person providing the information. In the case of biospecimens, the human subject is the person from whom the specimen was taken."
Reading that, it's clear that the Princeton study does not fit the definition of human subjects research. The complainants may be able to sue for damages to the university, but not because the study was improperly classified as human subjects.
"about whom" is a key criteria from the federal government to determine whether something fits the definition of human subjects research. Here's a quote from HHS:
"The phrase ‘about whom’ is important. A human subject is the person that the information is about, not necessarily the person providing the information. In the case of biospecimens, the human subject is the person from whom the specimen was taken."
https://www.hhs.gov/ohrp/sites/default/files/OHRP-HHS-Learni...
Reading that, it's clear that the Princeton study does not fit the definition of human subjects research. The complainants may be able to sue for damages to the university, but not because the study was improperly classified as human subjects.