I've deliberately avoided getting embroiled in this discussion, partly because it's the sort of subject that will bring out everyone's own prejudices.
Parents of people with Learning Disabilities - myself included - are fiercely protective of their offspring. But sometimes that can be counter-productive.
Mike enjoys music - he has a wide range of musical tastes. He loves going to concerts, loves listening to music - and thoroughly enjoys singing. To himself. Or in the shower. Which is the best place for it - his singing voice was inherited from me, and a thing of beauty it isn't. He does not play a musical instrument although he's had a few desultory goes at various percussion instruments.
He'd rather listen to good music than make bad music. He gets that from me, too. I'd hope he had the confidence to have a go at karaoke if he wanted to, but only because sober his voice is no worse than any given drunk. And certainly not because he has any additional rights over anyone else.
Ann's vague description got me thinking of campanology - remembering the combinations (as in ringing the changes), the dexterity required to ring the bells with clarity and to deaden the sound at the appropriate point, etc. No way could Mike manage that: daft to even consider allowing him to try. People would be looking for the fire engine

This is not twanging a laggy band over a tissue box, folks, and can't be brought to that level no matter how you try.
Equally, if the skill level required is less specific, some give and take is appropriate. Mike takes part in art classes. He is expected to deal with the issues taught, but can choose his own subjects within that. So when a piece of work involving perspectives was demanded of the class, he had to produce one - no easy ride for Mike. And he did it. With cartoon characters, because they were part of his comfort zone. However, his perspectives were absolutely spot on, which surprised
everyone except Mike.
If people like Mike are to be included in society, it will take give and take on all sides. Otherwise who's discriminating against whom?
Inside every older person is a younger person wondering "What the hell happened?"