There's certain individual or group that edited under the name "Icewhiz", was banned, and now operates endless sockpuppet accounts in the topic area to influence Wikipedia's coverage on the Middle East. One of them was an account named "Eostrix", that spent years making clean uncontroversial edits until one day going for adminship.
Eostrix got 99% approval in their request for adminship. But it didn't matter, because an anonymous individual also spent years pursuing Eostrix, assembling evidence, and this resulted in Eostrix's block just days before they became a Wikipedia administrator.
https://en.wikipedia.org/wiki/Wikipedia:Sockpuppet_investiga...
https://en.wikipedia.org/wiki/Wikipedia_talk:Arbitration_Com...
It's a useful contrast to a place like Reddit, where volunteer moderators openly admit to spreading terrorist propaganda or operating fake accounts when their original one gets banned. You don't get to do that on Wikipedia. If you try, someone with far too much time on their hands will catch you because Wikipedia doesn't need to care about Daily Active Users and the community cares about protecting a neutral point of view.
Not denying the existence of influence campaigns. There have been several major pro-Palestinian ones recently, which is probably why this letter has been sent. But the only reason you know about them is because Wikipedia openly fights them instead of covering them up. Most social media websites don't care and would rather you don't bring it to their attention. That is why Reddit banned /r/bannedforbeingjewish.