Operating expenses don't necessarily equate to total expenditure. The article also mentions that fifteen executives took home a six-figure salary in 2015; that doesn't strike me as particularly efficient.
Notwithstanding, what I originally said was not prescriptive. People are free to spend their money as they see fit. Even I have donated to the Wikimedia Foundation in the past and still believe that they provide invaluable resources for the common good.
Where I take issue is the fact that the messaging in their campaigns often gives the impression that the organization is scraping by on user donations, whereas in reality they're sitting on a pile of assets that would ostensibly be in the 99.9ᵗʰ percentile of household net worth in the US.