Alas, I think it's partly due to the anonymity that descends upon some people who are disabled. By that I mean: you hardly see any wheelchair users (and so on) when you're out and about in town so people assume that there is not a lot of disabled people who live in the UK. When in actual fact something like 10,000,000 people living in the UK right now are disabled to some degree or other. TEN MILLION!
But we don't see them, because being at home is easier than going outside.
Having a disability can shrink your horizons. It is bloody hard, frustrating, annoying and difficult to be a wheelchair user in an able-bodied person's world. This is why gaming is such a great thing for people who stay at home more. (I'm writing this as a disabled person, too)
Having said that, much of the admiration for you Gareth is not really anything to do with your disability; it's down to the fact that your play style is simply fantastic - especially when most noobs can't play with their hands!