So... you are effectively arguing that WotC has a moral obligation to control its speech... in the way you want them to. This seems in general form exactly the same as those saying they need to take it down. You both are trying to press an obligation on WotC. It is just that one is for up, the other is down.
Answering quickly because about to work out (so if any of this sounds curt, it isn't meant to be).
This isn't what I am trying to say here. I am saying there are moral questions around free expression and access for them to consider here. I am not saying what that conclusion has to be. But I do think the second part of your answer "You both are trying to press an obligation on WotC" helps make my point that people pressuring WOTC to take it down are controlling speech. After all if you think someone pressuring them to keep it up is someone saying they have an obligation to control speech how they want, them surely someone pressuring them to take it down is also doing the same thing.
I think it is a long, long stretch to call a supplement for a luxury entertainment game 30 years gone, "an important work."
To be clear here, I was not calling it an important work of literature or anything like that. Outside the hobby, our books are pretty much unknown. But within the hobby, sure it is an important book (at least I think you can make a good case that it is). I don't think importance is the only consideration here though. I was talking about importance works because of the general principle and how this pressure technique, if it can be applied to OA, can also be applied to something like the Godfather (which is an important work).
Never since the creation of the printing press has a publisher had an obligation to keep works in print. Yes, it is a bummer - but it is not the publisher's job to save you from all bummers.
Again, I am not saying they have an obligation to keep a work in print. I am saying they have an obligation to consider the morality of printing or not printing it. This is especially true when they are stewards of someone else's work (as is the case with OA), and simply hold the rights to it (because them sitting on the rights and not publishing it, when there are lots of people out there who might want the book or might want to publish it, raises issues of access to it). When you are a publisher you have power over what people can read when you hold the rights to something. That isn't a morally neutral thing. Does it mean they have a legal obligation to publish it? No, of course not. But I do think this is a much more complicated issue of free expression, access to media, etc than people are making it out to be. And I think they would see that if they inserted other works rather than OA into this as hypotheticals.
And, quite frankly, this flies in the face of that whole "freedom of expression for the creator" stuff. This "moral consideration" has been brought up several times in these discussions, in different forms. What it really amounts to is a statement that the public is entitled to the work (on some moral grounds), once published. That you have a right to someone's speech, even if they don't want to speak!
Needless to say, as a moral argument, that makes little sense.
Again, they can make this decision. But we can voice our opinion about the decision. And I am not talking about rights here. I said explicitly this isn't a 1st amendment violation. That doesn't mean it isn't censorship if a publisher who is otherwise happy to publish something, removes a book from publication because a group of people use social media to pressure them to do so. It isn't the government coming in and taking away peoples ability to see the material, but it is using other levers of power to help achieve a very similar result.
Also, very importantly, this isn't WOTC's speech. This is not a book they originally published or wrote. It is a book they have the rights to. Can they choose not to publish it? Yes. They can absolutely do so. Should they choose not to publish it? My feeling is that deprives people of a book they should have access to. In the grand scale of things it is fairly minor. It isn't like they are plunging some monumental work of literature into darkness. But bit by bit, this kind of thing does matter. And in the hobby at least, it matters. And it is okay for people to voice their opinion about it.