This should be a cautionary tale when you take money. Nobody gives “Free Money” they expect something in return, It might not be a bad thing, like some accountability where the money is going or they might want a say on how your organization is run, but its not free.
BY taking the money they gave him the right to give his opinion on something and its not so simple to shut him up. He might stop giving the money which is probably in the millions per year. Other Giverim might follow and say somethiong too on a topic, You cannot dismiss them all.