I work in social care, mostly with people who have learning difficulties or what is oft referred to as intellectual disability - we don't use the term 'special needs' anymore, I don't think anyone in the field does, at least not over here.
Part of my job is to advocate for service users, and to assist them as they work toward integration in the community. When I started, just 5 years ago, I was shocked at how some members of the public [albeit a small minority] would almost recoil in horror if one of our guys approached them to say hello or God forbid, offer a hand-shake greeting. That has changed significantly, just within the past 2-3 years alone, because people are seeing these guys out and about in the community more, they've gotten to know them by name [and their individual character] through asking questions instead of speed walking away or completely ignoring them. They're not hidden away like something to be ashamed of anymore, they're just as much a part of any community as everyone else.
If a person with a learning difficulty is in a 'main stream' school, they have been assessed and past fit to attend that school, they are not merely there to make up the numbers. There are indeed specific schools that cater for people with more severe learning disabilities. So this is puzzling to me, they've been accepted into the school, and no doubt accepted by their class mates, so why then seperate them for group photos? The photographer in this case really needs to brush up on their own learning difficulties.