It's not re-using so much as renaming. The were two modes for C, one of which was the original and default, hence having the name (and associated namespace) of `c-mode`. This name was changed to point to the newer tree-sitter based mode, which was I suppose a way to mark it as the "default" but left the original mode without a unique name.
Among the many comments of praise and agreement there are several that reflect the impression I've gathered from your conduct in arguments on here, which is that you have said things in the heat of debate that are more emotion than rationality.
I don't think it's a big deal, and I'm not really interested in examining this in any greater detail.
see also this nice response on the mailing list: https://lists.gnu.org/archive/html/emacs-devel/2024-11/msg00...
> This person is a raging lunatic;
I daresay you haven't an unblemished reputation for sanity yourself.