The design of Discourse as a platform is that posts are primarily surfaced through a feed style interface, rather than a rigid hierarchical forum structure like traditional systems such as vbulletin.
Because of this, there isn’t much advantage in trying to enforce strict categorisation beyond what tags already provide for the end user. In most cases, it works better to simply create the post and allow discussion, reactions, and discovery to emerge organically through the feed.
That said, I’ve heard this place may be on the chopping block. Even so, I’ll keep responding to anything that catches my interest, as long as it continues to land in my inbox.