"Editing your own article on Wikipedia is not prohibited as long as you disclose your conflict of interest and follow the rules[...]"
That's just the point though, they are not following the rules. FTA; "While the research behind the 144 named donors who gave more than $5,000 to the WMF is not yet complete, it is already clear that several dozen of them are not widely notable enough to have a Wikipedia article associated with them", "While a few have adequately disclosed their conflict of interest, most have not."
"[...]so I have trouble seeing how this submission is anything other than yet more manufactured controversy and/or anti-Wikipedia astroturfing."
If they are getting away with not following the rules because they are donors, then that is different from people who don't obey the rules for other reasons.