The general consensus in that thread is that, while the Vision Pro can play “flat” porn videos on sites like PornHub, there is currently not an easy way to play 180 degree side-by-side videos on the Vision Pro, which is how most commercial VR porn is filmed.
If you read the article, this has nothing to do with porn.
The built-in video player doesn’t support SBS 3D video, but third party apps do.