I don’t think there is, sorry!
My guess is that it’s that way because almost every app wants to handle that a little differently, and wiring it up yourself is exactly as easy or hard as your requirements.
For example, if you want to delete a user outright, all you need is a button/link, a route, and to call Users.delete_user(id). Not really worth building a UI in pow for that in my opinion, though maybe some docs would be helpful.
Or, in a lot of cases, you want to deactivate a user, but not delete their row to keep data integrity. Probably there are authorization considerations around who can delete or deactivate users. Those are all things that pow could do but it varies so much app by app that they probably didn’t think it was worth it out if the box. That’s a lot to maintain and would probably create a lot of support requests from people who want to change it a little to suit their needs. Probably the time was just better spent elsewhere. Although I bet they’d be willing to at least consider a pull request if you want to give it a go.