Using my above requirement, the case is made by Richard Stallman:
  <http://www.gnu.org/philosophy/motif.html>.  However, how the
  NetBSD project perceives this, is up to NetBSD.  I just want to
  be able to qualify the software I install.

The question here is not whether any individual will accept the
openmotif license, but whether it is sufficiently harmless that the
system will in essence agree to it for you.  RMS's rant convinces me
that it shouldn't be automatic.  I suggest filing a bug report that
the license is not acceptable under the description in
bsd.pkg.defaults.mk:

  #ACCEPTABLE_LICENSES=   fee-based-commercial-use no-commercial-use \
  #                       no-profit limited-redistribution shareware
  # Whitespace-delimited list of the types of license which are
  # acceptable for installation.  (apart from standard "free" licenses
  # such as Berkeley/CMU and GPL).  Possible values are presented below.

Include a patch to bsd.pkg.defaults.mk, x11/openmotify/Makefile, and
licenses/openmotif-license if you would like this fixed quickly :-)