Side question. I have noticed for a few weeks now that since I don't have a Medium account I'm prevented from reading certain articles (like this one), but I st

Side question. I have noticed for a few weeks now that since I don't have a Medium account I'm prevented from reading certain articles (like this one), but I still have access to some other articles on the platform. Does it mean that some authors require that the readership be part of the network too? What are the rules?