I'm sorry but you are incorrect on the cruise lines charging more for Accessible cabins just because of sq footage. The cost of an accessible cabin will be the same as any cabin in that same category. Thank goodness the Cruise lines don't have your same feelings on what is discrimination, or morally right.
You may want to do a bit of research on this subject, here is a quote from DOT and PVGA on how they handle different categories of accessible cabins when the ones that are needed are not available.
The Department recognizes that some existing vessels may not have accessible cabins in all classes of service. PVOs, (passenger vessel operators*) however, cannot properly impose costs on disabled passengers because vessels lack accessible cabins in some classes of service. If a passenger with a disability wants to travel in a less costly class of service, rather than a more expensive class, but the PVO has chosen to make adequate numbers of accessible cabins available only in more other expensive classes of service, the PVO must make accessible cabins available to passengers with disabilities at no more than the cost of the class of service the passenger requests. Under a nondiscrimination rule, disabled passengers, like all other passengers, should be able to purchase accommodations they can use at a price they are willing to pay." As well accessible cabins can not be at a higher price for the same class of cabin.
An example of this non-discrimination rule is that on our next Allure sailing we wanted to sail in an accessible JS, as none (a year and a half out mind you) were available RCCL rules had to upgrade us to the accessible Crown Loft suite for the same price as the accessible JS. Yay!
Given your feelings (or lack there of) on disabled needing to pay extra for the room they require, this probably doesn't sit well with you. But don't worry we won't be taking up space on the flow rider, zip line, skating rink, miniature golf, sports courts, rock climbing wall, even though we payed top dollar to sail just like everyone else. This should make the shareholders happy!