Having faced that choice myself once, I simply refused to do anything further for the horder rescue, who was really only concerned with making money off the rehome fees, (my friend called this his ransom demand) while passing along the operating expenses, and the work involved, to foster homes and volunteers.
Quietly, behind the scenes, people simply stopped Fostering for him, and advised anyone who would listen NOT to place a bird with him. While it was a bad situation for the birds he had, no one wanted to pay him his rehome fee anymore, and most folks wanted to see his "rescue" set up before signing their birds over to him. (Once they did, they didn't sign.)
When he couldn't make money anymore, and it in fact cost him money, he lost interest in doing it anymore. Eventually, his remaining birds got placed, but sadly, many of them died of neglect...
As an aside, there are places that solicit donations by posting pictures of horrible neglect that tug at our heart strings... where they themselves are the purpetrators. Find out if it's legit before donating money. They may be photos of some hoarder's basement, because this is how they keep the money rolling in. THEY are not helping the problem, THEY ARE the problem. Trust me - it happens!
There are many, many legit worthwhile places that need help and donations. If you give, check it out first, and give only to the ones that are worthy...
LIFE LESSON: THERE ARE TIMES WHEN IT IS NECESSARY TO REHOME. I GET THAT. BUT DO NOT SIGN YOUR BIRD OVER WITHOUT CHECKING IT OUT FIRST!!! ONCE YOU DO IT THERE IS NO GOING BACK!!!