Can't 'Disable' User

It seems that this has stopped working Disable User and was replaced with Delete User. I am having a problem using the “user delete” because users may have open issues, or issues that created or are assigned. I am now trying to figure out how to deactivate a user by flipping the “Has access on site” toggle.
I know that removing users from “Confluence-users” deactivates the confluence access, but I am unable to find the aformentioned “Has access on site”.

Can anyone please help me with how to accomplish this?

I think I need a way, through the API, to mark a user as inactive on the “Managed Accounts” page.