Let me put it in ways you'll all understand:
Say lil Jessica is the hottest girl in school, by 11 year old standards. Say every little Mormon boy there wants a dance with lil Jessica, but say Jessica doesn't wanna dance with all of them. Maybe she thinks some of them are weird. Maybe some of them don't bathe enough and they stink. Either way, she doesn't wanna dance with them. Come dance time, Jessica only wants to be with her friends, but nope, she's got a bunch of 11 year old kids coming at her from all angles to dance with her. She can't say no, it's in the rules. Now, Jessica feels uncomfortable. Now, all those Mormon boys get to have their turn dancing with her, even though she feels uncomfortable. Don't you think lil Jessie-poo should have the ability to say "no, I don't wanna dance with you?"
This isn't how it works, though. You have a list of names written beforehand of people you want to dance with. Can't dance with the same person twice, and when the card is full then you're done.
"The district said Monday in a statement to McClatchy that participation in the school dance is voluntary and explained that students are taught various styles of dancing, such as line dancing, in PE before the event."
They're taught dances so one can only assume they'll get a partner from their card for each of those dances IE Lil Jessica dances with Lil Timmy for line dancing and then another for this other dance.
It doesn't appear to be the bump and grind type of dance. They still have those events where they can say no to people.
Why do you want to force young kids to dance with other kids they don't like?
Its weird
They're not forced if the event is voluntary. Forcing them would be making it mandatory but it isn't.