Comment by abugheratwork

Protocols allow for namespace restrictions on CA certificates. There could, in concept, be something stopping you from spoofing google.

https://www.ietf.org/rfc/rfc2459.txt - section 4.2.1.11, Name Constraints

Given that I don't think you can actually buy that kind of cert, and the term "CA" is accepted to imply "universal CA", you're correct.