That is a meaningless/incorrect sentence. If you change "defined" into "major", then you are right, but then your point becomes irrelevant/moot.
BTW, Google Groups and similar sites *do* use NNTP for the (peer to peer) *transport*/*copying* of articles, so your point is irrelevant anyway (because we all agree on *that* part).
However on the *newsreader* side, NNTP is, as said by several people (including Floyd and myself), not the only or mandatory method. Forget your apparent dislike of GG/web/HTTP/et_al for a moment: Do you really think that people who read from the 'spool' or SOUP (guess what the 'U' stands for) or ... are in some strange way not reading/posting_to 'real' Usenet/News?
FWIW, I have been, professionally, managing and using Usenet/News servers for 21 years, i.e. from the pre-Internet/pre-NNTP days, so believe me that I have a reasonably good idea what is and what is not a Usenet/News server, and let me tell you that Google Groups *is* a Usenet/News server (just not an NNTP one one the *newsreader* side).
If it wasn't so sad, it would be funny: Normally people say that old people (like me) are stuck in the past, but these threads show that many young/'new' people are stuck in the present. Anyway, as I mentioned in another post, NewsReader.Com, , is the killer argument. One *cannot* argue that NewsReader.Com does not provide legitimate Usenet/News access, but at the same time NewsReader.Com invalidates Galen's claim. So Galen's claim is false. Period.