Here's Facebook's blog post about this situation: https://about.fb.com/news/2021/08/research-cannot-be-the-jus...
Right. Ad revenue is the only acceptable justification for compromising people's privacy.
Edit: Although research is a valid justification for compromising people's wellbeing[1]
[1] https://www.theatlantic.com/technology/archive/2014/06/every...