we provided an alternative script for OmniFocus a while ago to add a tag to hooked OmniFocus tasks , which illustrates the concept: Configurable Tags.
So if the Drafts AppleScript dictionary allows it, it would be trivial to add.
Personally, I think this should be the default for all apps that support tagging, but I know not everyone agrees.
I’ll ask someone here to have a look. meanwhile we have some volunteer liaisons for Obsidian, and hope to have one for each major app, like Drafts, who would check for things like this, and interact with the other dev’s community if needed.