No small undertaking and not to be attempted without due thought and consideration!
I'm not at all sure you'll find the Voltaire-esque illumination you've asked for, but there may well be an immediate and obvious reason for that.....
There is nothing to disagree with in your preceding posts where you present the position that nothing more, or less, than amenity and the submitted justification for requesting consent for works should be considered in the decision making process that precedes a DN.
On that we are in complete accord.
Where, I think, we may diverge slightly, is that (I presume) you exist in a highly professional, fully resourced, experienced, qualified and equipped environment where consultee input to DNs is given all of the necessary attention and staffing prior to submission to the PO and as such, you may not have been exposed to, or even be able to comprehend the possible existence of, poorly conceived, inadequate or blatantly "made up" statements, requirements or conditions attached to DNs which eminate from (dare I say it) less well equipped, resourced and motivated working environments than I imagine yours to be?
And so, whereas enlightenment may be beyond my ability, it is with much regret that I may actually need to bring to your attention the disappointment that can be experienced when exposed to organisations with less qualified, experienced, engaging and professional staff - yes, I'm sorry to be the bearer of such devastating news, they do exist and the empirical evidence is here on this forum and within my own personal experience - where, it may be felt that, DNs can appear to be justified by 'amenity' (subjective and almost impossible to define) in order to avoid any deeper staffing of the application. Purely a personal opinion, but the A word can be the refuge of the inexperienced or overworked TO and whilst it may well be enough to deter the random homeowner applicant or equally over-worked and ambivalent contractor, in the long term, (again, a personal view) it's does no credit to the shared aspiration of achieving real amenity.
Perhaps we could re-visit the discussion when the outcome of this particular incident is in the public domain?
Beer O'clock!