I picked hosting because it's a line item that exists across all of their budgets, it's a rough proxy for a web business's non-salary expenses, it's a big part of what you think you're donating to based upon Wikipedia's own language in their fundraising drives, and if nothing else, it's way more forgiving to the growth of their expenses than consumer price inflation is.

Ultimately every person has to decide for themselves whether they think WMF is a worthy recipient for their donations, but it is in no way operating on a shoestring budget nor staffed by volunteers anymore.