Until the server owner confirms the trusted list, anti-nuke only alerts — it never removes anyone's roles. That is deliberate: Defendr does not know yet which of your administrators are supposed to restructure the server. Open the trust page, add the people and roles that may, and press Confirm trusted list.
Example
You add your two co-owners and the Staff role, confirm the list, and the response changes from Alert only to Remove dangerous roles and time out for 7 days.