Then go to a different signing entity. You know why virtually none will supply a cert for windowsnotificationcentre.com? Because the domain is deceptive in nature and nobody wants to back such an obvious malware site.
This is hardly an arbitrary decision - notificationsforwindows.com would be fine, because it's not directly using a trademarked part of the world's most widely used desktop/laptop OS. But windowsnotificationcentre.com is obviously trying to sound like an official part of the Windows ecosystem, being named exactly like a component on Windows.
Let's not, since that's a complete non-sequitur. MS isn't challenging the domain, nobody have ever said MS is challenging the domain. Biker himself complained that the cert should be available since the domain was validly obtained.
All MS (and Let's Encrypt and StartSSL and any other legit CA) are doing is refusing to validate that domain.
And so they shouldn't. Biker can generate a self signed cert for whatever domain he gets, but he can't get international recognition if the domain is likely to appear to be from a separate recognised organisation.