He doesn't have an obligation, but he also willingly chose to be the face of HBCU. He was constantly talking about bringing up HBCU as a collective, shining lights on it, building up the infrastracture, connecting with the recruits on a personal level etc etc.
He was there maybe all of 2-3 years? he did amazing in his role & helped absolutely. But from the outside looking in It sounds like the same move we've seen over & over from black celebs in the past. They market something as for the black community, they galvanize black people into supporting it, they build success & the second a white person comes with a giant check they either join them or sell their company to them.
In a business standpoint it's amazing business, & his choice isn't necessarily wrong & i don't think he deserves this large of a blowback but i completely see why people would be frustrated with the situation. As black people we constantly talk about needing our own & building up our own, we always seem to start it up & just abandon the actual purpose in chase of the money or noteriety.
Again Deion doesn't owe them anything, but he also volunteered himself as this savior of the HBCU programs