Sure making things more usable may sometimes have trade-offs. But I'm struggling to think of the disadvantage of basic markdown support on a site where everyone knows markdown, and even assumes it is supported. People are constantly posting markdown lists that end up all on one line.

I assume the reason it hasnt been fixed is that nobody can be bothered, which is fine. But it's still a little embarrassing. Kind of like how Stackoverflow doesn't support triple backticks. I often see questions with formatting screwed up because people assume a site that heavily relies on markdown supports an extremely common markdown feature.