1. Because the easiest "solution" was to just add "readmore" to the list of approved HTML tags.
2. Because this node contains <!-- readmore --> (here:) but contains no <readmore> tag.
3. Because eventually we should provide a better solution that offers links like
   • "read less" (redisplay this node but with READMORE bits hidden)
   • "read more" (default thread display)
   • "read all" (redisplay this thread with all READMORE bits shown for all replies)
   • "hide replies" or otherwise adjust the replies depth to display
   • etc.
   and (we hope) have "read less" only appear if there is a <readmore> hiding in the current node.
4. Because our nodes are rarely "valid" so only crazy people try to have them validate and a tool called "HTML Tidy" shouldn't require you to tidy up the HTML before you give it to it. q-:

We also should eventually have a [ ] readless option during Preview.

                - tye