Damien

If a charity immediately gave away all the money that had been donated it would fold pretty quickly. They do need to be set up to deal with soliciting more donations, managing the money and managing the logistics of getting that money to where it would be needed. Medical charities need to investigate which research is worthy of funding for example. Red Cross and Oxfam often have to work in complicated places to access and work. All of them need to ensure they keep getting funding to carry on doing what they do and that also costs money.

Yes the Red Cross could empty it's bank accounts at the next crisis but then they won't be around to help the next time. Staff, equipment, travel, medicines, offices, and the ability to process future donations don't come free.

Listen to a interview with Bill Gates about his charity. It is mostly his money and that of his wealthy backers but many times he has talked about the amount of effort, logistics and time that happens behind the scenes to make everything work.