I agree, along with the child comment. I think the issue is that if there wasn't some kind of ability to "rug pull," that we would see far fewer open source contributions in the first place.

I hate that a company can take a fully open-source project, and then turn it into a commercial offering, dropping support for the project's open source model. I am fine with a project's maintainers stopping support for a project because they have other things to deal with, or just are burnt out. I understand that both of these things are allowed under the specific license you choose, and still believe you should have the freedom to do what was done here (although not agreeing with the idea of what was done, I still think it should be allowed). If you want to guarantee your code is allowed to live on as fully open, you pick that license. If you don't, but want to contribute as a means to selling your talent, I still think the world would have far less software if this was discouraged. The source is still legal from before the license was changed, and I feel that even if the project doesn't get forked, it is still there for others to learn from.

With that said I'm wondering if there has ever been a legal case where source was previously fully open source, then became closed source, and someone was taken to court over using portions of the code that was previously open. It seems like it would be cut and dry about the case being thrown out, but what if the code was referenced, and then rewritten? What if there was code in the open source version that obviously needed to be rewritten, but the authors closed the source, and then someone did the obvious rewrite? This is more of a thought experiment than anything, but I wonder if there's any precedent for this, or if you'd just have to put up the money for attorneys to prove that it was an obvious change?