Should disabled kids be kept out of the public eye?

Recently, a waiter at a restaurant refused to serve one party after hearing them make fun of a child with Down's Syndrome sitting with his family in a nearby booth. Both parties were regulars to the restaurant. Some people have praised the waiter's actions because he took offense at overhearing the first party say "special needs kids should be kept in special places." He called them on their rudeness and refused to serve them. Others think he was wrong: his catering to the party with the disabled kid is indicative of a culture that embraces mediocrity and disability. What is the proper assessment of the remark made and the waiter's response? Should people with disabilities be kept from public view?

See: http://rt.com/usa/waiter-garcia-family-syndrome-681/