I came across an article on the spiritual needs of persons with intellectual disabilities. Among other things, it speaks of 'one-hour friends', persons who genuinely welcome someone with an intellectual disability to their church, for example, but who invite everyone except that particular person to social functions. There's no malice whatever - rather the contrary - but the one left out can be deeply hurt.
Jean Vanier, through L'Arche and through Faith and Light is very consicous of this. This time seven years ago I was in Lourdes on the International Faith and Light Pilgrimage that takes place every ten years. Faith and Light grew out of a special pilgrimage to Lourdes in 1971 for persons with intellectual disabilities. It had been organized because of the experience of some such persons and their families not being allowed to join other groups of pilgrims.
Many old people with various forms of dementia can also be unnecessarily isolated, as I discovered when involved between 2000 and 2002 with the Pastoral Care Project, founded in 1995 by Frances Molloy in the Archdiocese of Birmingham, England.
Every human being is made to 'know, love and serve God', is unique, has something to give that no one else can give and has unique needs. Many are born with learning disabilities. Many others, when they grow, old lose to some degree their mental faculties. But they have their personal history, their memories. The latter may be dormant but can be awakened by a piece of music, for example, that stirs up emotional memories.