I'm not going to read over this whole thread, because a lot of it is a case of tl;dr (not that my post below isn't that either - as disability and travel is a topic which gets me really ranty.
On Mr Crocker
Travel for disabled people is a big issue, but on the balance of what has been written about this specific case - I'm going to side with the carrier. This is also the first time I've heard of his name in respect of such issues (and have used my google-fu to check around just in case).
If Mr Croker is a frequent traveller, he should have known better. He knows full well there is a call for pax w/children, elderley and other impaired persons before the priority and general boarding calls.
If he had to avail himself of the bathroom in close proximity to departure commencing, given his specific circumstances and needs he should have approached ground staff and informed them of same so they could plan accordingly.
QF did everything reasonable to re-accomodate the pax on next available, and offered some form of olive branch in consideration for what happened (the latter being entirelly unnecessary IMHO).
<rant>
On disability/medical needs and air travel in general
Air carriers know that people with disabilites and medical needs will use their services from time to time, and they do everything reasonable and practicable to accomodate their needs. In some cases, they even go above and beyond the legal requirments for equal opportunity and access.
The flipside of this is that there are limits on what they can do, and a level of personal responsibility and cooperation falls on either the disabled/medical assist pax or their designated carer to work with the air carrier to achieve the best possible outcome.
Further, carriers make every effort to communicate this information to such persons ahead of time - through multiple formats, channels and even to relevant disability/industry groups to ensure every possible chance of pre-informing this cohort of customers.
If you are disabled or have medical needs, and fail to make contact with an air carrier a reasonable time before departure, they simply can't be expected drop everything to accomodiate your every need and desire.
Like anything in life, things take time to organise. Power points for CPAPs, medical oxygen, extra staff to assist mobility restricted pax on board, or safely stow important equipment can't be done with the click of the fingers. If you can't take the time to plan ahead and ask questions before you travel - than frankly neither I or the public at large should have any sympathy for your plight whatsoever.
If you fail to plan, you plan to fail.
</rant>