People can post whatever they want. The forum is not the build compendium you know. For the compendium, it reads that for a build to be included in the compendium it has to be more or less finished. Since this build can fulfill c+ and sr tags for HC, I would say it is definitely compendium material since it is “more or less finished”.
This is the actual phrasing
“While there never was a formal rule on character level of your build, it is a tradition to only submit builds that are at level cap or close to it.”
When it comes to just making a thread about a build, people can post whatever they want - there is no rule or guideline regarding that (Common Sense Rules for Build Posting)