It says "make a JOYFUL noise unto the Lord" - it says nothing about having to be tuneful!
We had a few difficult kids in our choir when I was a kid - our choir mistress had a terrible time with Warwick. Harvest Festival, Warwick nicks an apple from the altar. He's walking along, tossing it in the air and catching it - when the preacher walks past the other way, catches the apple mid-air and puts it back on the altar.
My mother took over the choir for a few months, while her friend was in hospital. She got annoyed with Warwick one practice and had him come stand down the front where she could keep an eye on him. But this meant he was nearer her perceptive ear and she stopped us. "Warwick, sing that last verse again, but on your own this time."
He did and we were gobsmacked. What a voice! After that, Warwick was groomed for solos and actually began to behave a lot better. He was given more challenging music (ie put in with the harmony kids) and began to do really well in other areas.
Another boy, Mark, was also difficult at times. Our conductor was back from hospital and used my mother's trick - "Mark, come stand down near me, see if that helps you stand a bit quieter."
Mark tried, he really did. He was a good kid at heart, but the conductor's ear heard the poor boy couldn't hold the note. And we were about to enter a really important competition!
"Mark, try that note again - no, dear, that's sharp. Go a little lower. No, that's too low." She tried to help him, by now he was feeling awful. She let him go back to his place and listened again - with other kids on either side he could manage a little better, but she could still hear the off note. She rearranged kids around him so he had a strong, accurate voice on each side of him and we swung into practice. At no time did she suggest he would have to leave the choir because he was tone deaf.
And we won the competition - WITH Mark! Interestingly, Warwick was in the same competition but not with us - he was now a soloist. Much better behaved these days. I can't remember how he did - third, I think.
If you give a kid a fair go, try to find ways around the problem, you do a lot better. And any kid who really wants to be there - there should be room for them to be there.
One of the choirs we were competing against used to compete around the world. They had a blind girl in their ranks. The other girls would hold her hands, elephant parade style, to help her into the correct position on stage. Nobody was left out. And they were really good! (and we beat them - yay! A huge honour).
Marg