You could argue that if all the celebs that took part in Children in Need donated a couple of percent to the fund instead of tap dancing or whatever shit they get up to then the same money could be raised instead of public involvement. The public involvement is a part of the whole process, um.... lest we forget.
There are a lot of charities sat on fortunes, my missus works in cancer research, the 'sciencey bit' not the fund raising and they have to do a sales pitch to the charities (although technically working for a university) for funding. I have heard that the British Legion is sat on gazillions and gathers far more than they dish out but that's anecdotal. Charity is an industry now, we'll all have ones that are 'closer to our hearts' than others. Charities are run by people, charities head hunt people, its an industry, by all means, cherry pick YOUR charities, we all do, I just don't get the need to single out charities for criticism unless they've been caught being up to no good financially. A lot are by the way, some spend quite lavishly on their HQ's etc but my spider senses aren't picking up that this is your logic.