Necessary Series Disclaimer: I am not a lawyer. The information presented in this series is based entirely on my experience as a creator and curator.
One of the benefits of living in a connected world is that we can enjoy creative work from not only our own country, but also from around the world without having to wait for someone in our own country to acquire a license to bring it into and share with our country (although this is still a very common way to legally experience books, music, television, and movies from other countries). But with this ability to experience all of this global work comes a whole new discussion on copyright.
You see, copyright is assigned at a national level by the nation where the copyright holder legally resides. Within that country, those wanting to use or share the artifact have to play within that country’s copyright laws. But when someone outside that country wants to use or share the artifact, it’s not so cut and dry. Countries would have to sort out whose copyright laws prevailed in matters of sharing internationally, up until conventions were established to facilitate sharing copyrighted materials across borders: the Universal Copyright Convention and the Berne Convention (which you have seen named on movies since the US joined in 1989). Note that there is no international copyright, just national participation in one or both of these conventions.
We encounter this in our lives especially on YouTube, where creators can decide to what degree they are willing to be protected. If they want only their own country’s copyright laws to be in effect, they won’t share the video internationally. If they are fine with it, then they will. Some companies and personalities prefer the often stricter protection offered by their national copyright laws, and so they will restrict distribution. Some creators (individual, personality, or company) will find they have numerous barriers to jump through, and will have to wade through international concerns to make their material available globally.
This is effectively what you’re running into when you hop on YouTube or a media site and are informed your region doesn’t have access. There’s often something going on in the copyright, either deliberately selected by the copyright holder or enforced by copyright laws. The copyright holder may simply not have the right set of rights to make something available internationally. (I can’t confirm this, but based on my own experience as a YouTube creator, videos are internationally available by default. If someone has more experience with this, feel free to leave a comment.)