I have often read on HN that not accepting a PR for a feature that is not tangential to the core business of the project is valid and understandable when the maintainer believes it will require too much resources (bug triage, fixes, documentation, short or long term support in the forums, etc.) from him.

It is useful information for potential users to know how the project works and if it might not fit them well. There's no contract or agreement between the maintainer and users. Users are free to talk about the project. As long as they don't demand anything I don't see the issue at all.

How exactly is this complaining? I am merely making an observation, not even in the earshot of their devs. I had evaluated Lapis years ago, but quickly moved on when it didn't seem adequate. I didn't complain about that in their issue tracker then, and I am not going out of my way to bring this up now because I am holding a grudge like you are implying. Whether or not they add websocket today wouldn't matter to me in the least, I am simply indifferent to it.

> it is logical that the main developer who used it to build itch.io is not going to put in the effort to do something they don't care about

There are plenty of frameworks that add features well beyond what the devs need for their own products. All I am saying is it might be more logical for other people here to use those instead. Of course people can come to this conclusion on their own, but highlighting what I believe to be a key information may save that time.