[You're 100% correct, it doesn't belong there.]
Hrvoje Niksic <hniksic(a)srce.hr> writes in xemacs-beta(a)xemacs.org:
Why is etags.el a part of the "core lisp" rather than being
an
installable package?
Because of the problem of building the etags binary. This will get
addressed before we release a stable 21.x.
Although I dislike many features of the current packaging system, I
am
always in favor of doing the job thoroughly. In this case it means
that etags.el should be made a package.
And apropos.el, hyper-apropos.el, etc. ...