The process is quite simple and requires only that the owner or administrator of the Facebook Page install the Facebook application. The application can then use the "disable composter for users" feature (https://developers.facebook.com/docs/messenger-platform/send-messages/persistent-menu/#disable_composer) to prevent users from posting to the Facebook Page and instead only show them only a menu.

However, the problem arises when the application is uninstalled and the composter remains disabled. Only the original application, which has a user ID, can turn the composter back on. None of the original Facebook users who had the composter disabled will be able to post messages to the Facebook page in Messenger.

Even a "good application" is unable to use this feature for real-world cases, as it is nearly impossible to re-enable the composter for thousands of users after the app has been uninstalled, due to a request limit. Additionally, if the user who installed the app changes their password, the authorization token becomes invalid and the application loses access to the Facebook Page. Similarly, if the Facebook Page administrator uninstalls the application directly from the Facebook settings.

I have reported this error multiple times, but each response suggests it may be a UX error and not a bug per se.

¯\_(ツ)_/¯