In general, I disagree with the ability for users to delete their own topics or posts. I believe that if a topic gets out of hand, or a user specifically requests that a post or topic should be deleted if it is, say, damaging to their character, admins should have the right to step in and exercise their judgment. This, of course, depends heavily on the admins being decent human beings who aren't on a power trip for shits and giggles. So, in this day and age, that's pretty much a pipe dream. The thing is, it obviously can be done, this site is a pretty good example of that. However, I stand by what I said. There's nothing that will teach you about etiquette, or oversharing, or a host of other negative consequences of saying things that you maybe shouldn't online, quite like having a mob of faceless usernames wiping the floor with you and picking apart your stupidity bit by bit. Even if you were right and you know it, you might learn a thing or two about how people think, and/or develop a thicker skin as a result. Caution, even a healthy dose of paranoia, is a great thing to carry with you in this time we're in where even an unassuming username can be traced back to you. The old, trite advice about not saying something online that you wouldn't say to your grandmother rings true, surprisingly.
There was another blindness-related forum which I was a part of for many years before it shut down. I found said forum as a teenager, and boy, some of the things I wrote there were cringeworthy. My responses to the criticism that was hurled at me were pretty shameful. But I still wouldn't change it, because it taught me a lot of things, too much to go into on a post like this. I don't believe that having an easy out, i.e. deleting your own posts, is beneficial in the long run. All it does is teach you that you can slip away from harm you may have caused unscathed, and that's really not a good message to be sending, whether you're 12 or 100.
The glass is neither half empty nor half full. It's just holding half the amount it can potentially hold.