It would be if they weren't working with the IETF to have their additions become HTTP 2.0.

There's no difference between Google extending SSL, implementing that in their browser and servers and then submitting it to the IETF and Microsoft adding additional features to SPDY and submitting those too for consideration.

Only when their changes get turned down, but then still appear in IE in such a way that it only supports the changed SPDY but not the original any more, only then I would have to agree with you.

At the moment it doesn't look like that is the case though.