ERHS is in Prince George's County, which, while well-off as far as majority-black counties go, is far from the wealthiest in the area (due in part to the structural difficulties of building and maintaining black/brown wealth in America). To be frank, it
is in one of the wealthier and whiter parts of PG, but it remains a diverse public school that largely draws students from the surrounding community. If Google or Brin were to donate to either the school or the county, it would
decrease inequality in comparison to competing jurisdictions (e.g., Montgomery, Fairfax, Anne Arundel, and Loudon Counties, let alone DC itself).
This might not hold for other cases, but it really does in this one.