Except it does matter how much a contribution for the poor, is eaten up with administrative expenses. It is very expensive to run the largest, oldest organization on Earth.
Sure it is, but they're still providing a massive amount of donated time and money to help the poor. I recently heard the same criticism regarding the Wounded Warrior Project. Their overhead is atrocious, about 40-50 percent, but they bring in over 300 million a year because of great marketing. If the bad press kills the program, there's a shit load of money that's not getting to to disabled vets who need it. And without the marketing, people aren't going to give to other similar organizations to pick up the slack.
The Church is pretty good at fiscally decentralizing, so there isn't one massive bureaucracy controlling all the donations and distributions. I'm guessing this helps keep administrative expenses down.