They still must stay in alignment with the Law.
Wanting what you want is not a legal exemption.
Commercial DVDs (Video DVDs) almost always use CSS (Content Scramble System) encryption. Playing them requires libdvdcss, which is legally ambiguous or outright restricted in some jurisdictions.
Distributions, like Ubuntu or Zorin OS are restricted from supplying this in the same way as how they are restricted from supplying Proprietary drivers (broadcom is an example) or Microsoft fonts.
They do show you how you can get them on your own where it is legally permitted and as the Stance on Piracy makes clear: There are lines not to be crossed.
VLC is not a service, it is a standalone package, so it is not as restricted.
Why does Zorin OS not include it: VLC has had significant problems security side and would be a very controversial choice on many fronts.
As an aside: I spent well over fifteen years on Microsoft products before switching to GnuLInux and I can tell you, things did not "just work." From vague troubleshooting references, to try to hunt for answers on the web, to Microsoft Support networks, getting things to work was often like pulling teeth.
This guide is still applicable and accurate, but it shows a warning on the page that may apply.
In addition, variance in manufacturer coding may necessitate a user needing more packages like gstreamer1.0-plugins-bad, gstreamer1.0-plugins-ugly, and/or gstreamer1.0-libav.
sudo apt install gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly gstreamer1.0-libav