There's a 3-way social contract between the platform (Reddit/npm), the nominal person in charge (mods/module authors) and the users. If the person in charge does something that is sufficiently disruptive to users', or platforms interests, the platform will step in. We can argue about where the line is, but beyond that point, platform intervention is inevitable.
Edit: Thought experiment: would it have been acceptable had the author of leftpad put up a poll for downloaders to vote before taking the module down in protest?