But if its because of safety, why only JavascriptCore VM allow write execute flag?
If that was the real reason then, dont you think it should also be disabled in JavascriptCore?
Or the real reason, is as it was pointed out in the other comment, is to cripple other browser engines that offer a platform that could actually be competitive with AppleKit's turning their control over the App store (and what people are allowed to access according to their own taste) irrelevant?
And if that's the real reason behind it, its clear the end user best interests are not being taken into account, as in not having access to possible better options according to your own tastes, contrary to what a lot of people in the comments here are trying to make we believe its true.