A few people have noted the large number of large people at WorldCon. I've seen this at all the cons I've attended for the past 20 years, and have some thoughts to offer.
First of all, a world con is bound to attract more of everyone. People save up for and schedule vacation time and reserve plane tickets and hotel rooms for a world con who wouldn't go to a local con. Why? Two reasons: World cons attract more of the best writers, artists, costumers, performers and dealers. And world cons are Far Far Away.
World cons usually gear up more than the local cons for people in wheel chairs, scooters, skateboards, Nimbus 2000's, podracers and the rest of the teleporter-challenged. It's a chicken and egg thing.
So why all the big people? Well, there are not only big people, there are also the physically unattractive, the socially inept, and the hygienically repulsive. Why are these people drawn to science fiction? Well, mostly they are drawn to fantasy. How nice would it be to be able to wave a magic wand and suddenly be beautiful? Or to wave a magic wand and suddenly everyone loves you? The ending of Shrek 2 is classic that way - instead of making all the ugly people wish their fairy godmother could make them super models, they wish that everyone sees the Beauty Inside.
There are some who hope science will fix them, but my observation is these people are rare. Most of the large fans I have met who are rabid fans of star trek or star wars are not very interested in what a dilithium crystal is, or the physics behind a wormhole. They want to be like one of the characters. They're in it for the social escapism, the speculative sociology.
I understand that. I was a porker by age 12, in an era when it was the exception. I also was extremely shy. I still am - don't laugh - if you know me, there's a 99% chance you introduced yourself to me, rather than the other way around.
Another reason these strange people come to world cons is they know there will be others like them. They won't stand out as much, there will be new friends to meet who are Just Like Them, or tolerant of people like them. And nobody will nag them to eat smaller portions, or healthier food, or at more reasonable hours.
Now for the promised rant. The phrase "differently abled" makes me cringe. It's euphemistic and usually not accurate. Take two people with equal abilities. Chop one's leg off. You haven't given that person any different abilities, you've taken some abilities away. You have created a disabled person.
Yes, I know some people learn to compensate by honing other abilities, but that doesn't make them differently abled, that just makes them disabled and focused on better using what's still working.
Okay, a deaf person may learn to sign, isn't that a different ability? Not really, it's nothing a hearing person can't learn to do. And it won't help her talk to a blind person.