[zabuni]

The article basically implies they use exceedingly broad categories, and don't exactly characterize everything the way they should. See also this Propublical article:

https://www.propublica.org/article/how-the-red-cross-raised-...

There's a chart half way through that shows, by NPR and Propublica's estimates that instead of 90% spent on actual charity, they only spend 60%. This would tank their rankings in places like Charity Navigator and Givewell.

So the short answer to your question, is that they are vague as hell about how they spend the money, and they probably cook the books.