I’ve wouldn’t characterize it as a prepared speech. She was trying to express something emotional and difficult that made her feel vulnerable. Writing that kind of thing down really helps a person who feels uncertain get to the meat of what they want to say without withering from embarrassment or choking. Therapists reccommend it when a client is trying to tell a loved one how they feel. If she had read a poem she composed earlier or performed a song she made up, would they have allowed that? What about reading a quote from a book that touched her? Just because she wrote it down and read it doesn’t mean she wasn’t speaking from her heart.
Also, if was just a rules violation, there was a better way to handle it. Wait for her to finish, thank her for honesty, and then remind everyone to avoid “prepared speeches.” Cutting her off serves no purpose but to embarrass and shame her.
As for the “colluding adult,” if I was her parent I would be so damned proud of her bravery. I would totally want to record it. Not for some statement, but because I’d want a recording of my brave sweet kid opening up, possibly coming out publically for the first time.