The teacher seems like they were grooming the kids.

Unicorn cupcakes for the gay ones? A unicorn in adult terms is a bisexual who comes along and is willing to be used by both sides of a couple.

If it were just unicorn cupcakes in - say - a kindergarten setting with gnomes, that would be normal.

But they were already focusing on the kids' sexuality and then rewarding that sexuality with a symbol of going a step further in being exploited.