You only have one login method linked or removing the login will make it so that you cannot sign in to one of your apps. If you are unable to remove a login method, it means that it is either the only login linked to your account or it is required for a specific game or app. This is to prevent losing access to your account. To unlink the primary login method, you need to link a secondary login method using a different provider that is supported by all the apps you use.