They store that information on a cookie! Some websites try to break their own permission manager on purpose (or at least I can only imagine it's on purpose) by

They store that information on a cookie! Some websites try to break their own permission manager on purpose (or at least I can only imagine it's on purpose) by burying the cookie that stores the permission manager's settings within the list of cookies you have to accept or reject, so if you "reject all" you will be asked again and again. Non malicious implementations either include the permission manager among the essential cookies or list it at the very top so you can choose to keep it. If the permissions were managed by the browser then cookies could be managed directly on the client side without server side interference, and preferences could be communicated to the website via headers (like DNT but GDPR requires a lot more granularity, and is also legally enforceable in the EU).