SD,
As far as I remember, the clause I quoted existed way back in the XP days ? I don't think much of the actual legalese has changed.
Also, I believe there always has been a Microsoft requirement for most OEM software to be pre-installed on the system by the system builder (I certainly remember this being the case for Office and can't see it being any different for OS).
I don't think Microsoft are re-writing history. I think you'll find the intention has always there for the policy to be like that if you look at all the pieces of the puzzle .... the fact that there might have been a confused message is probably just down to good old corporate bureaucracy.