I've heard the red cross is one of the worst charities out there in terms of how it uses its money. Supposedly most of the donations just go to paying the salaries of the people running it from what ive heard.
It's not entirely uncommon for some money to go towards the running of the charity, including administration and wages.
How much of their funds is spent that way will vary from charity to charity. Some are run entirely by volounteers on no pay.
Obviously it's not good if 50%+ is spent that way, but it's not illegal as the money is being spent on keeping the charity running and no one is pocketing profits.
But yeah, while registration/certification is important it doesn't entirely prevent shady goings-on.