This seems like common sense. If you deleted any account tied to software purchases you would lose access. If I delete my Steam account I would not expect to have access to my Steam games that require their infrastructure etc.
Social media accounts are by their nature a large amount of photos, posts, tags, personal info that other people will see including employers, immigration officials, future dates. There are very good reasons you may want to delete it (and prevent future tags, wall posts) rather than just abandon it, so it becomes more problematic if you cannot without other penalties.