The song is a few years old, I think (is it on 'Revolution', 1970?), and I agree with you, John, that perceptions probably have changed as to these children's potential. I have a friend who works with them as a teacher. She's often in despair - more often than not because it's the parents who don't support her efforts - but one child with potential can lift her out of it. I admire her greatly, and also the parents who raised her daughter in order to make her as independent as possible. She'll never be able to live alone, and you can't deny a certain 'simplicity' but she's able to take part in and enjoy life.
Incidentally, I didn't mean the use of the word 'mongoloid' in any way derogatory. My friend the teacher affectionately calls her charges 'my mongos', and she's devoted to them. Still, for parents who are faced with all the problems this condition brings with it this may sound as though others are making light of them. Sorry! - Susanne