The organization involved in the production is non-profit and didn't deliberately set out to financially screw over Disney. The least Disney could have done is smooth ruffled feathers by speaking up and explaining their position.
I was involved with productions put on by my high school drama group and my Girl Scout group. The Girl Scout production was to raise money the providing solar ovens for 'third world' countries. (I've been at this stuff since the 60s) In each case we contacted the copyright holder and received permission to use the work.
Being non-profit or not trying to "screw over" the legal owner is no excuse for not following well known legal procedures.
I am sorry for the performers but they were ill served by those in charge of this project.