If you'd read the article, you'd see that it's because Apple hasn't supported SBS video - one of the most common 3d video technologies. It has nothing to do with imposing values. No reason has been given, although "SBS isn't supported to keep porn off their platform" is ludicrous conspiracy.
Perhaps they did not use specifically porn as the reason for not supporting it, but in any case this is hard to explain otherwise than a measure to make difficult the use of any content that is not provided through Apple, i.e. if this is not anti-porn it is at least an anti-competitive measure.
From what I've gathered, it's basically that they're mostly too low quality, compared to the AVP's resolution.
Apple wants to limit video to only a super premium experience, which they seem to be working on but it hasn't been launched yet.
In other words, they don't want the VR video experience to be the same as 4K or 8K SBS on a Quest 3, because then you'll just buy a Quest instead.
I'm not defending this, but I am saying there's a logic to it. The AVP isn't anti-porn (I'm sure you can watch the regular 2D kind on the web just fine, Apple isn't limiting your content there), nor is it anti-competitive. It's just not implementing a feature.
It's very tempting for a filmmaker to carry whatever techniques they are used to in traditional film and use a fancy camera to make it "VR". It takes a long time for the lessons we've learned to actually take root so we can tell a story without throwing the viewer around in some gravity-defying kaleidoscope of headaches.
Apple is up against a widespread misconception that VR means motion sickness for a huge number of people. Largely because of cheap garbage like Gear VR, and content designed for it.
This is factually untrue.
While the puritanical nature of the App Store is weird, particularly when they have no issue with drug and sex references in their keynotes. You are way off.