Dd goes to an all girls school. She's in y4 but since she started, the teachers have been very vocal in encouraging them to be "all friends with everyone" and not to have best friends.
To the extent that in reception, two girls were playing together each day and the teacher said one day "hello Gemma, Emma is playing with someone else today so you will have to find someone else too"
I guess I can see why, as intense friendships can turn into rows at that age. But aibu to think it's trying to make them miss out on an important part of growing up. I always remember my best friends even now.
Perhaps they will make best friends anyway (some I think already have, but dd not).