Wow, that is a pretty awful experience!

I don't think that anything I've experienced with a performing group has come to that level of "ick".

Youth Choir was the worst, and it was pretty good. The only problem was that the Music Director always wanted us to sing "kiddie songs" that the rest of the choir had sung since Cherub Choir. They were sick of the songs, and trying to assert their independence and adulthood, and the adults wanted them to remain kids.

The other worst group I was in, was the production of Godspell at that same church. The Director (a different one,) constantly bullied me, and refused to acknowledge the work that I did for the group. I was the first one "off the book" a full week before the lead star, and she only acknowledged him. She gave me no direction as to the interpretation of my lines. Three days before the show, she told me in private that I could't act, and she had only let me be in the cast because the music director had insisted on it, because I had a beautiful voice. She said she would have preferred someone else for the part. Such an encouraging thing to say to a young performer!
It was my second show ever, and my first one with any lines. I had a solo, which I did beautifully. But I don't act anymore. She is the first choice for directors in this area, and I refuse to work with her.