without considering themselves either immoral or hypocrites, then they believe something different from what they think they believe.

Is 'immoral' the best word to use in this context? If you asked them, 'do you think you are as moral as possible or are doing the very most optimal things to do?', I suspect most of them would answer 'no'. Problem solved, apparently, if that was what you really meant all along...

And donating to charity until I become a charity case is unreasonable- if donating to charity is a moral obligation, at what point does it stop being a moral obligation?

You already explained at what point donating stops. As for 'unreasonable', I think that's more rhetoric on your part since I'm not sure where exactly in reason we can find the one true ethics which tells us to eat, drink, be merry, and stop donating well before that point. If it's really unreasonable, you're going to be picking fights with an awful lot of religions, I'd also point out, who didn't seem to find it unreasonable behavior on the parts of ethical paragons like saints and monks.