Its not like games that tried to be realistic before didn’t exist and not like games that purposely go for a non realistic style now are not a thing. I’m pretty sure we have more pixel style graphics games coming out now yearly than when they were actually a thing.
That just enforces the idea that people with disabilities are not a normal part of the society. It’s like asking to justify why a character is tall, blonde, old, a woman. People are just people and there’s a huge variation on their shapes, sizes, colors and disability status.