Penny S said:
" The number of people who have been silenced by thoughtless teachers must be immense."

I think that happens because the students are put in a choir format. As I earlier stated I don't have a lot of range and because of this my choir ability is limited. Now if it was me who chose the key I could have done much better. Also a student may have more interest if they are singing a song that they like rather than one picked by the teacher. A good teacher would work more with the individual instead of forcing them into a mold but that requires effort.