I really don't understand why an analysis of how this letter was mailed is important. Are we supposed to assume he is an asshole just because he has an assistant? I self identify as a writer but I work for myself so does that mean I am not really a writer?

Yes, he sent his daughter to a "liberal school" but that liberal school made major changes to its curriculum, and its calendar in the last year. There are now numerous meetings on race, a required commitment to racial training by parents etc. It also appears that there are race segregated meetings. As a parent I would find this problematic to say the least. That student body should be united in its educational journey and not segregated by race.

Further you fail to mention his complaint that while the school is compelling students to attend all these meetings on anti-racism the school is not changing its admission criteria. The school has not committed to changing its legacy admissions which favor rich white people. So the school wants to further the diversity story but doesn't want to give up its gravy train. To me that is hypocrisy. The story behind this letter is much more nuanced than you portray which is sad given the importance of race relations today and our need to have an intellectually honest discussion on these types of issues.