The giant operating budget is what people take issue with.
People see these banners on the website and assume that their donations are going to fund the website. However, the Wikimedia Foundation has been inexplicably expanding their budgets to match whatever amount of money comes in each year, leading them to this endless cycle of needing ever-increasing amounts of donations because they're doing ever-increasing amounts of spending on various activities unrelated to serving the website.
Remember: the WMF less than ten years ago themselves said they could survive quite well on "$10M+/year".
https://lists.wikimedia.org/pipermail/wikimedia-l/2013-March...
Now they ask for $160M+.
At some point the message has to change. It has to become something a little more like: Look, so far we've done this which you thought was cool. Now we want to do X, Y and Z. Will you support us?
They have had some marginal change in hosting fees, so a 1200% change in costs seems reasonable?
I think this is a perfectly valid idea and would encourage you to lead with this sort of approach in trying to get the Foundation to change strategy. It's straightforward and constructive. Pointing out all the ways the fundraising is bad is not nearly as useful as suggesting ways to approach it differently and improve it.
(I normally don't talk about Fundraising stuff as a volunteer, but the Meta thread where I was pinged led me here).