There are red lines beyond which a person should be considered socially radioactive and ostracized.
In my example of Weinstein, it remains a worthy cause to help people with AIDS, to prevent new infections, fund research, etc. But now maybe people hesitate to donate because of how they dealt with Weinstein.
In the case of media lab, obviously there are people making their career there who have nothing to do with this Epstein controversy. Now they may experience a sense that they are also tainted.
When such an organization turns a blind eye to this problem, they risk harm towards their stated goals and they do a disservice to employees, other donors, those who believe in them, etc.