There are things to criticize wmf spending on, but the above is absolute bullshit. It is simply not true that "95% of spending, including 90% of staff, is on things with no relation to wikipeida".
In 2025 they spend 184 million, and 2% was on hosting. Even several times that for salaries means that an absurd fraction is on non wikipedia items.
Software doesn't write itself, and improving the software for Wikipedia is where the lion-share of the budget is going.
That doesn't even get into less technical roles like legal or community outreach, which are very much spending for wikipedia.
Hosting is a small portion of the budget because its by far the cheapest part of running a major website. In many ways its also the easiest part to make cheap, simply by not using AWS.