Except, since it says no such thing, no.
Wrong. It's become a norm that Usenet posts can be retained and, without
modification except to add Xref etc. headers, redistributed:
1. For a limited time (typically up to three months) by news servers, so
in practice by pretty much anybody; and
2. For an unlimited time by archives (so in practice by pretty much
anybody) unless marked X-No-Archive: Yes.
Consequently, making a Usenet post may be construed as granting an
implicit reproduction license as described, but that license can be
construed as expiring after a short time in the presence of the
X-No-Archive: Yes header, whereupon any explicit license terms would
apply, or, if none was present, the default "all rights reserved".
Of course, unless the poster registered their Usenet post with the
Copyright Office, they could not sue for damages, only for an injunction
to stop infringing uses. (They could also still use the DMCA to take
down copies on US servers.)
In practice, the poster would probably use Google's own methods to
remove their post from the archive after the fact, and this would
probably work; otherwise they'd use a DMCA takedown notice, which Google
would probably respond to; and only sue if that also failed.
However, the law does allow someone to skip straight to suing someone...