The difference is that Apple runs the App Store and agreed to allow app developers to opt out of publishing their apps to the Mac App Store. In order to facilit

The difference is that Apple runs the App Store and agreed to allow app developers to opt out of publishing their apps to the Mac App Store. In order to facilitate that they had to implement DRM. Being able to run arbitrary code doesn't really mean you get to run other people's code without their permission, which is essentially what running those applications on a mac was. You can argue the merits of DRM and copyright of course, but ultimately that's not the same thing as "running arbitrary code." You can run the code and that code includes a check to make sure the platform is one that the developer approved of. If you find a way to remove that check it probably still runs.