I actually can see the MS perspective of not allowing applications to directly modify the default application for a given purpose. If apps can never do it, it removes some amount of vulnerability from OS. Applying fixes to block applications that work around the OS’s safety features seems valid to me. In this case, I don’t think I could reasonably claim this was MS’s concern/intent in breaking Chrome’s default app button, I’m only saying that I can imagine legitimate reasons to do purposefully do that.