This article is from the alt-sources-mac FAQ, by Mark Pilgrim (firstname.lastname@example.org) with numerous contributions by others.
A bunch of clever linguists have asked on alt.sources.mac why the group is
not called alt.source.code.mac, alt.source-code.mac, or alt.sourcecode.mac.
Some people feel that "sources" is an ambiguous term which implies that
people can freely post questions like "Where can I find X?" In fact, they
are right, but their linguistic arguments are largely irrelevant.
Alt.sourcecode.mac does not fit into the Usenet naming hierarchy. Like it
or not, there is an established naming scheme, and source groups like
alt.sources, alt.sources.amiga, alt.sources.d, alt.sources.index,
alt.sources.patches, and alt.sources.wanted were around long before
alt.sources.mac came into existence. There is no alt.sourcecode.* hierarchy.
This name policy is enforced by a group of influential news administrators
who manage the large sites (like uu.net) that directly or indirectly provide
newsfeeds to most of the world. This naming scheme has been around for a
long time, is very widely accepted, and was an important consideration when
these people agreed to create alt.sources.mac.
In short, there is nothing we can do about the name "alt.sources.mac". It
may be confusing to people who are unfamiliar with the group's purpose, but
that's what FAQs are for. If you're really adamant about trying to change
the name, please discuss it in alt.config, NOT in alt.sources.mac.