Quest is open because you can sideload. Apple is not. See the recent article where Apple says they'll block porn apps however they can on vision pro. Not cool,

Quest is open because you can sideload. Apple is not. See the recent article where Apple says they'll block porn apps however they can on vision pro. Not cool, it's a really great tech for people with an open mind. SexTech is a fast growing market and imposing morals on your users isn't a nice thing to do. On quest you can just sideload such apps (though unfortunately sidequest no longer allows them in their store either after they started working with meta). Nevertheless you can still just sideload the APK directly even through sidequest. Which works fine.