If you click through, for example in Germany, you get a pretty detailed explanation of where your money goes:
https://spenden.wikimedia.de/spenden/Ihre_Spende_wirkt
The largest part: support for volunteers. Isn't that what Wikipedia is all about?
That's the heart of the issue, right? Is the Wikimedia Foundation just supposed to run a website that is edited by volunteers, or is it supposed to also do other things that further the same goals as the actual Wikipedia? The foundation itself has the latter viewpoint, while I expect most people donating are just donating to pay for the former.
Please put numbers on the table, because I expect "most people" to be fully aware of how that non-profit thing works.