I don't know about OP's DD but I'll give some examples from my experience.
Child told off for tale telling, because it isn't "nice". Incident including another girl following them to the toilet, calling her names , trying to look under the door,climb the wall to look over and kicking the door while she was using the toilet.
Told that she should tell the teachers and give them a chance to sort it , instead of telling mum. It's not nice or fair to keep quiet because then they can't deal with it.
Told off for excluding said girl and not wanting to play with her ,that it's not nice AFTER being kicked and her hair pulled by same girl.
Told that x has a,b,c issues and she needs to be kind and understand that. Massively unprofessional and a breach of privacy for that other girl.
Most schools and staff are great, work incredibly hard ,do their best and most ant their best for their kids. Some suck or try to take the easy way out. It happens.