I've just read this whole thread with interest and a little frustration.
The way I see these things is much the same as anyone that wants to find a school or organisation that they feel they fit into. People have to look about, talk to schools etc and find the places that accommodate their needs.
Some people want more survivalist courses, some want fast paced, some want physically demanding, some want more relaxed, or not so physical, some want short ones and others want as long as possible.
Everyone should find the place, be that a company, organisation or friends that works for them, that make them comfortable and they enjoy the experience. Not everyone can be accommodated by everyone/or companies etc. That's unrealistic and I think unfair on them, who should be free to chose where they run their business, who they accommodate etc.
If someone has a disability or a particular need then I am confident that they could be accommodated but the right company, it's a case of finding that company and building a relationship with them. I'm also fairly confident that if anyone approached a company with a group of like minded people that made up enough in numbers a bespoke course could be easily commissioned. It's also worth pointing out that we don't generally put children with adults and children are much more likely to be split by age/size etc to accommodate physical and mental abilities.
As for the comments about disabled people not being welcome I think that if they came and asked what they could do in bushcraft, what's possible, has anyone got suggestions to help with a craft or skill then people would bend over backwards to give input, be encouraging etc. A specific request for help would likely be much more answerable.