It's not really good reason since they don't endorse specific country when they accept certain fiat. And it's rather ironic when Wikipedia promote similar ideology (free and open knowledge).
I didn't say it's the best reason, I said I can't argue. It's the same as they would have said "because we no longer want that".

And for the rest... there used to be a saying: "do what the priest says, not what de does".

I would say that that was their stated goal, but it has been captured and is now peddling a highly skewed, non-independent, biased and non-objective form of "open knowledge."
This is easily a feature of centralization and a result of getting far too popular.
Agreed. The centralization and capture of wikipedia is problematic.
They are dissatisfied with the large consumption of electricity that is spent on bitcoin and ethereum mining, so they made such a statement. Let's wait and see what happens when ethereum mining ends.
So they claim, but that is naivete, ignorance, or a conscious goal. Without PoW, security becomes an issue which may be their goal.