If they admit that he isn't the monster they claimed he was, they'll have to look in the mirror and admit that they behaved exactly like those they claim to fight (Zionists, fascists, Nazis, etc.). That's why they make a thousand excuses and remain silent.
They know they went too far with their harassment and violence; that is why they refuse to acknowledge this donation or are making excuses. It is evidence that contradicts the entire narrative they constructed to justify their gratuitously violent behavior toward him.