And there it is! It IS WITHIN THE BIRDS CAPACITY TO DESIRE SUCH! That has been and is the point. You simply refuse to accept that people actually do desire their sin. Because you cannot stand the fact that you love your sin as well, apart from Christ.
This would all be valid if it was within the birds capacity to desire to fly but it’s not. You’ve already said the lack of capacity to do something removes one’s culpability for not doing it and you’ve also admitted that men are not capable of desiring, thus contradicting yourself.