It is a myth that you should choose the charity with the lowest administrative expenses. Getting resources from donors to areas from need involves labor. Labor is not free, and when it is performed by highly skilled individuals, it is not cheap. Non-profit administration requires a particular skill set, and it has to be paid for.
You could drive or fly to Oklahoma and start tossing cash randomly into the air or throwing cans of soup into people's yards. You'd be performing "charity" at very low cost. (It still would not be free, because you'd have to pay for transportation to get there, and take a few days off work.) Personally, if I'm going to give my money to charity, I'd rather give it to people who know what they're doing and get paid appropriately, rather than hand it to some dude plans to sling soup cans.
Are the administrators of the Red Cross overpaid? Yes, probably. But in the end, I'd rather they do well financially and get the job done at some level of competency, as opposed to running the cheapest possible operation. I don't write the cheapest essays, and I don't expect other people to work for rock bottom prices, either.