Are we so cold hearted, that we lack compassion?
It’s not about compassion.
That is the key. A few schools hire professionals with real talent, but most schools hire the hack who charges the least. That rookie knows that some parents will buy the class picture, no matter what, and others won't - again no matter what. Why bother working to get a good shot or accommodating differences such as the kid in the wheel chair, when you make the same money for a mindless point-and-click, not to mention that he probably doesn't have the talent to do better?
It's not insensitivity to disabilities, just insensitivity to everyone and everything, an unprofessional attitude.