I never understood it either. I mean, as a religion.
What is even sillier, is that as far as web forums are concerned, you have 50% of them which will go mad if you "necropost", and the other 50% which will go mad if you open a new thread when there is already an existing thread on the same topic (even buried), because these have the exact opposite written or unwritten rule. The latter ones love their 800 pages long topics; the former ones forbid you to follow up with a discussion even when it is the exact same topic, if the discussion stopped for a while.
A random person online invests an afternoon to read through a years old issue thread and decides to comment, expecting the maintainer to reply. Meanwhile, maintainer has dozens of such issues, and dozens of frustrated users bringing up each of them every week. Asking the submitter to respect a previously made maintainer’s decision, file a new issue and invest their own time to concisely summarize the status quo seems only fair.
In other words, diverting discussion to a new thread is a chance to compress old context into a short summary, like you would squash a Git history—except in this case the old closed issue thread is fully linkable and isn’t going anywhere.
[0] That said, it depends on maintainer’s personality. I can see how some could feel losing control and demoralised by ever-evolving difficult-to-track discussions on previously closed issues.
What you describe is about the community respecting foss maintainers; closing tickets is not going to solve this problem.
