https://aaas.fas.harvard.edu/people/claudine-gay
So Harvard employs, as a full professor, someone whose Ph.D. thesis contained loads of plagiarism (I’ve seen the evidence, it’s not contestable). A similar offense on the part of the students who sit in her classroom, according to Harvard’s own rules, could lead to expulsion.
EDIT: Also, as pointed out in a comment below, Prof. Gay’s Ph.D. is from Harvard. It was not revoked.
I remember it was technically initiated by the Harvard business school, but it was probably triggered by data colada launching their own investigation.
This speaks to your point.
But Gay's PhD was not revoked.