It's a good question.
I agree with you. I always say that harassment is in the eye of the person filing the complaint. What is offensive to me should be investigated. If it's determined at the end of the process that it's not harassment in the eyes of the law or the legislation, then provide the rationale for why it isn't.
I recently was involved in three situations at the very same work location under the very same employer. One was a complaint under the employer's policy. Two were grievances. All three were dismissed. In one case, there were 69 allegations against a co-worker, and these same employer representatives dismissed all three sets of allegations saying they did not meet the definition. When we addressed the concern up to the higher command, the response we got was that “you don't have to like the answer but at least you got one”.
If DND is going to promote zero tolerance, then the persons filing the complaint have the right to be given due consideration. In one of the incidents that I identified, a third party actually recommended to the base commander that an impartial investigation be done. The base commander declined the opportunity to do an investigation although it was recommended.