It's not mysterious at all. But if every neighborhood is allowed to opt out of change, the result is a free-rider problem. Exclusionary neighborhoods can free ride off of the neighborhoods that actually allow new housing, businesses, walkable amenities, etc.
He was a mensch for this. He did a lot of stupid, evil things as president. But when he had the chance to leverage public opinion against a vulnerable minority, for personal gain, he said "no". Imagine the current crop of criminals showing even this baseline level of integrity.
if academics went to therapy, they might realize that "you cannot expose someone's wrongdoing if it might lead to them committing suicide" is textbook abuser rhetoric