Not to mention being able to delete ones posts in app by oneself is not the user data deletion in the common GDPR speak. There it means all data in an organization which can be linked to me, and I have a right to request companies to delete this data, and they have to do so in a timely matter. That is not a requirement for all companies to allow users of them to do it themselves, which depending on the companies data structure would be ridiculous (e.g. imagine every company suddenly having to setup an user account system just so users can delete their data by themselves :D)