On a factual level: Yes, the people who maintain this board have enough brains to figure out an auto-line-break (or "insert <p> tags" feature). That's what I infer from my dealings with them. So my guess is that not having this feature is a deliberate choice, rather than dumbness. A lot of message boards resort to inventing their own tags to allow for formatting. For a site like this one that caters to programmers, I find it an excellent choice to just give them all the expressiveness they want by letting them use what they already know: HTML.

Regarding the validity of the HTML generated -- PM has grown over the years, and little bugs can be found here and there. You can help the site maintainers by giving appropriate feedback.

On a personal level: Looking at your post, I get the impression that you are trying to pretend that you want PM to improve, but actually you want to show that you know things better than those who are too dumb to figure out auto-line-break features. Or maybe you are retaliating against someone who told you not to parse HTML using regexes. Well, hopefully I'm wrong.

At PM, we tend to not take ourselves or Perl too serious. That helps in maintaining good relationships and actually getting work done.