This isn’t a perfect solution, but I have had some success building a workflow that met my criteria and having the action. be to remove the unwanted association labels.
If you haven’t turned it on already, this beta “New Workflow Actions for Associations” is pretty slick. It allows you to add, update, or remove associations in a workflow which weren’t previously available.
Hope that helps, but I do agree, it would be nice to bulk upload this.