I think it's more about not having control over one's own content. For that reason, I don't post everything I want to as well. This limitation means that you can not even post a progressive tutorial or something like that, which is a bummer.
It's arguably not your content any more once you post it. It's part of the continuum that is the thread of discussion.
This board does not make clear the rights and right holders of a post. For example, Stack Overflow and the Stack Exchange sites license everything under one of the Creative Commons licenses. And, as a contributor, you agree to licensing your content that way.
I know other boards where they explicitly take ownership of the content you post. As a contributor, you are adding to the board, and the value of the board. So, it's in the boards interest to maintain control.
Here, there's simply "© 2002-2019 Vintage Computer Federation, all rights reserved" on EVERY PAGE, which suggests that, indeed, the board retains copyright. But that's not made explicitly clear in, for example, the Board Rules, that as a contributor you are granting Copyright to the board. Maybe it was in the disclaimer thing we clicked through when we signed up. (It's not, I checked, it's just the same Forum Rules they have posted.)
But since this is the boilerplate we have, that's the way it is.
For example, the board could republish your work in a "Best threads of December 2020" news letter, or simply redistributing it via an RSS feed. That's all publishing, and the board needs the rights to the work to do that.
We're all friendly here, so "nobody cares". No doubt the editing limitation showed up simply because of some bad actors in the past. "This is why we can't have nice things."
But when push comes to shove, this is the board resources, their publishing platform, and, at the moment, "their" content -- we just write it.
If you want to own your content, start a blog on a platform that respects your rights as a creator.
And if you want to do a progressive tutorial, do a progressive tutorial. Magazines in the past have done that for ages. And they publish errata when things go awry. At least here, folks can respond directly. And if you have a real issue with a post, contact and admin.
And if someone wants to ask an admin to clarify their IP stance, that'd be super duper too. But, I'm not going to ask, it's not that important to me.