I totally understand the thing about Montessori and the rules. Seriously, I could not believe the number of rules in my son's class. He came from a daycare where the rules were be nice to people and property. Just getting to circle was a multiple step process that had to be in order the exact way. It was hanging a coat, changing shoes, and washing hands. Sounds simple but there was a specific way things had to be done, there was a line at each station (single file, no talking) and if anyone didn't walk between stations they had to go back to the one before. Circle was long. Sometimes forty minutes. Even though kids could pick their work, they had to do it exactly as the teachers wanted. You couldn't mix works either. Taking the "pink tower" and making snowmen who lived on the cutout of Pluto was frowned upon (despite it being great snowman habitat ;)).
Anyway, you are not the only one shocked by all the rules. I was admittedly uneducated about preschool philosophies when he enrolled. I just figured he'd be great anywhere because he loved learning. You'd think that would make school easy.