Hot air

I understand offering your skills to help a charity.
I understand going to a meeting to discuss the details.
I understand sending a proposal about how you can help.
I understand receiving the charity's response with a few queries.
I kind of understand six weeks silence, since it's been summer.
I don't understand saying it's not really the best use of your skills after all, at 6pm on the evening of the deadline for submitting the funding bid.

(Not Richard Branson, though he'd also be welcome to make an offer should the mood take him.)