My money's on total ignorance of copyright law. In a world where people post videos with disclaimers of "no copyright intended," I can believe that someone could think that a work they don't own can made open source by simply declaring it so.
Looking at the whole account and Wikipedia edits, I'd guess that it's either a troll, a child or a person with some mental illness thinking they do good.
You're probably right. I just have a hard time wrapping my head around that level of wilful ignorance. It's worse than programmers who think they can "hack" the law.
I don't think this is willful ignorance -- comes off to me more as a child or mentally ill person who means well but doesn't understand what they're doing. Did you see the screenshot of the Microsoft support conversation that they posted as proof it was open source? https://i.redd.it/9zkgslagked21.png
