there is no reason those shouldn't work on players in other regions.
Other than, of course, that the company which produced the content wants to sell it that way and today has the right to do so.
Actually I have read the spec for HLS and it does not specify any restrictions on the operating system, handling of keys, or handling of decrypted content.
The fact still remains - your issue here is with "DRM" as a concept, which is perfectly fine. I honestly don't think it matters to most consumers.
In fact, Consumer oriented DRM should be illegal. It's an anti-competive anti-consumer dangerous practice.
How is it any more anti-competitive or anti-consumer than copyright in general? If your issue is with copyright why not just come out and say it?
Adding features does not necessarily increase functionality -- it just makes the manuals thicker.