No, the article makes it clear that you can visit whatever website you want.
The "issue" is that the current version of Safari on Apple's Vision OS won't take "180-degree side-by-side" video - which has different channels for the left and right eye - and play it back with just the left channel going to the left eye, and the right channel going to the right eye.
Instead it shows a single flat video window with the right and left channels shown in each respective half of the window.
This 180-degree SBS style of filming is how most commercial VR videos are made - from YouTube to YouPorn.
I see what you mean. The article used the phrase “X-rated guardrails,” which made it sound like it was censoring by type of content.
I don’t know much about VR headsets. You mentioned that “180-degree SBS style of filming is how most commercial VR videos are made,” so why did Apple choose not to support it?