Sorry I forgot abou this
Point 1: having third party program’s which are not control of the oem opens problems for a midrange of problems. You cannot trust what bugs, software testing methodology, malicious intentions the piece of the software might exhibit. It is better to simply build a system that is semi open and semi closed. This being metro and the traditional desktop. The metro aspect of the browsing space is willing to go to ms with ie. they simply want an easy consistent experience that users will enjoy with minimum problems. They are also doing so to sidestep anti competitive practices and erring fines by the eu (again) how? By limitation metro browsers for consistenay but allowing those browsers to be used in the traditional desktop.