First, after quick review, it looks to be true---except the part about "alleged".
Second, in short, no.
Third, longer answer --- "disparate impact" is generally used in terms of employment law. Trustees are not employees. And "legitimate" carries the connotation of lawful. The law is on the books, therefore it is legitimate. It was, however written in a much different time. There is reason to question the legitimacy.
In fairness, I find it to be something that should probably have been done away with years ago. Only not now---not when, to the best of my research knowledge, it has never been challenged in the legislature and not questioned until such time as it is convenient to cry "unfair" in order to extricate ones self from an embarrassing situation of ones own creation.
And on a hopefully humorous note, it was probably written to prevent these guys from doing what every other board of trustees in the state was doing at the time
I am waiting for the review of the construction contracts before I get too stoked. There's gonna be some good stuff in there.