Epic poets adopting, stitching, recycling, riffing, borrowing from other sources is appropriate for the medium of and vocation of poetry. It's appropriate for an oral tradition in oral societies.
Universities are not institutions of oral societies. The scientific method is not an institution of oral societies. Reproducibility and falsification of claims would not be possible.
The idea that a research university president should be held to the standards of ancient poets rather than the standards of a research university is silly. Citation of the provenance of one's claims, ideas, facts, data, and methods is central to what makes a university and university and what makes the production of knowledge using the scientific method a success.
If Dr Gay wishes to take the works of others, remix them, put her own spin on their work, integrate them into her framework, then she should go into the arts and become a poet or lyricist.