You cannot point to any other similar procedures in any paragraph of
the IFR or Nonradar chapters nor can you explain how, when, where, or
why these unreferenced procedures would be applied.

Because it's irrelevant. The point is that non-radar towers DO issue
headings, even when the aircraft will not immediately vectored after
takeoff. I could speculate on the why, but you're in a better position
to know than I am, if you will acknowledge that it happens.

This is why the distinction between a "vector" and a "heading" is
important.

Whether the initial heading into a DVA is a vector or not is a matter
of semantics. A better description to me is that the heading is an
unpublished ODP. But a pilot receiving a heading can't tell the
difference between one that will provide obstacle protection and one
that won't.

In Wally Roberts article "Radar Services Terminated", he doesn't
directly address the vector vs. not-vector issue, but instead focuses
on the issue about when radar contact will be established. If not
established within one mile, he shows a strong inclination not to
accept any heading that differs from a published DP or SID.

There wasn't anything on TV :-(

There never is. I haven't watched it in 4 years. I hope you have
better plans for your retirement than watching TV and scanning
newsgroups. ;-)