I think your preschool teacher is both a bitch and a complete idiot.
But that's coming from both a vet, and someone who worked with / taught ADHD kids for years.
Where there is no curbing wild behavior by being strict, if anything all that does is make things worse. Working within
that disorder is quite backwards from neurotypical kids. As punishing and restricting? Just means that they come up with more ways to be punished and restricted. (Don't climb the clock tower! ... Just means they'll climb the car. Don't climb the car!... Just means they'll climb the bookshelves...you've have to create a thousand don'ts, and they'd still find 400 new nouns to climb. Or they'd quit "climbing" and start heaving, sliding, springing, dragging, as more and more verbs are restricted. Shrug. Giving them a "When is it okay to climb?" Checklist, on the other hand? Works a treat. Just like a "When it okay to yell?" Checklist -When there's danger, or you're far away.- "When is it okay to jump on furniture?" -When you've asked, first, AND they've said yes.- ). Instead of
Don't be bad!, it's learning how to be good.
Shrug. It's very Montessori in many ways. But then Montessori education was originally special ed for difficult & unteachable children. It was only later found to be also brilliant with neurotypical kids. In most Montessori schools the examples you listed would be "So & so is learning how to be a good friend / is struggling with being a good friend, today." Or "Amazing Climber is learning when and where it's a good idea to climb." Or "We're getting a lot of opportunities to practice being respectful to others. That can be super challenging, huh? High five for how hard you were working at that today!"
Writing off behavior simply because kids of normal parents do the same thing is not in the best interest of the child
It can very well be.
If something is developmentally and age appropriate? That's a good thing to know.
It's tempting to brand kids with whatever is going on nearby them, even though the kid next door does the exact same stuff and doesn't get branded as anything else other than a representative of childhood... And that both puts undue pressure on them in some regards (to not be kids) whilst being overly permissive in other regards (excusing behavior that in no way needs an excuse, and needs correcting). Essentially doing the opposite of what that individual kid needs. Their normal stuff being branded as unacceptable, and their hard stuff not being helped though. Instead of their normal stuff laughed off as just kid stuff, and their hard stuff being given a hand with.