I have a similar story. This was in the 80s in San Francisco even. At 3, my son was all about DUCKS. Quacky pull toy, rubber ducks in the bath etc. A friend and her 4 year old met us on a Saturday and we were off to the park to feed the ducks. Her daughter was wearing barrettes with little plastic ducks on them. She took off one and stuck in my boy’s hair. It was a present from his friend and it was a duck!! Happy day, ducks everywhere, even in our hair! So on Monday morn, time for me to go to work and no way was he gonna go to preschool without his duck barrette in his hair. Ok, I indulged him, figuring it would fall out by the end of the day and he’d forget about it anyway. The preschool ladies went berserk . “You’re gonna make yor son GAAAYYY!” And I go , Calm down. He’s a child. He likes ducks. But as soon as I left they took the barrette away from him, which made him sad. Because of rules, they told him.So to cheer him up I had to read him some storybooks, and he was learning about rhymes.
When he discovered duck rhymes with truck, he ran around hollering “DUCK TRUCK DUCK TRUCK” for days. Like to drove me nuts.
Nowadays , the preschool ladies would want to put him in a dress and help him “transition.” They won’t let a child be a child.