I can certainly understand this. While administrative costs and overhead are always going to be a fact of life, some charities manage it better than others, and there will always be "greedy executives" looking to take their cut.
I donate both my time and my money but I do it for an organization that I'm heavily involved with myself so I know exactly where the money is needed and where it's going. Yes, I've seen money get wasted (and sometimes it's even my fault) but we learn from the mistakes and take care not to repeat them. I find it much more fulfilling to be able to help an organization from this intimately close perspective than simply to be writing cheques from afar.
I'd call myself as much a devout Christian as the fellow you quoted, yet I believe in none of the above. Why? Because of the scientific evidence to the contrary. None of the above are issues of faith. Yes, you'll find some fundamentalist Creationists who believe the above, but that view isn't shared by all Christians, nor is it taught as fact in the Christian Bible. Go ahead, look it up.