As I was at pains to say, It’s not wrong for the not-frum-enough philanthropist to make any donation he wants, and its not a halachic problem (at least from the perspective of hilchos tzedaka. It may be an issue of maaris ayin or chilul hashem) to take his money even if you wont take his kid. But it sends an immoral, hypocritical, inequitable and dissolute message to all those I mentioned earlier and to the entire oilem that elitists will reject you and your kids but take your money.
As I have been saying (a few times already) Just because one CAN do something doesn’t mean one SHOULD.