The SBSK guy knows his audience; they're the same type of people who seek out inspiration porn, follow disability hero social media accounts, and obsess about other people's disabled kids. There are way too many folks like him, and his fans, crowding the healthcare and education systems. They get off on this and have the side benefit of discussing their pet interest in ways that make them feel superior and benevolent.
I ran a program designed to give kids with serious physical, intellectual, and mental health challenges activity time at a university sports complex. Some of the parents were great, but a lot of them fell into one of two categories - overprotective and smothering or way, way, too interested in their child's disability to the point that the poor kid seemed more like a hobby or a way to show off how wonderful and put upon a parent they were to this oh so very challenging child. These are the kind of parents who love to parade their kid's on shows like SBSK. I'm sure there are lots of normal families that involve themselves in 'advocacy' of this sort, but they're outnumbered by the medical mommas and their ilk.