Observations
The General category seems unnecessary from a user and community host perspective.
From a user perspective, it's essentially an Off Topic category. (Admins can create that if their community would benefit from the category.)
The General category seems to be No Category in terms of Peerboard's back end--link from General as a post's category is to the site url not a category number.
When the category in which a post was created is deleted, the post is not reassigned to General so much a uncategorized and displayed as General.
Suggestions
It would be better for posts whose category is deleted to default to Uncategorized.
If the option must remain on the Select a Category, it would seem to be better for users to have the option of posting in a community defined category or in Uncategorized.
As Admin, I'd prefer to have the option to remove Uncategorized from the Select a Category menu when a user is writing a post. (We have a catch-all category.)