Parents express anger about their preschool’s ‘best friends’ rule

What do you think of this?

Last year,  children attending the Pentucket Workshop Preschool in Massachusetts were told that they could no longer call anybody in their class their "best friend." A mum of one of the students, Christine Hartwell, told Boston 25 News  that her daughter was "upset" by the rule. Her daughter, Julie, was just four-years-old at the time. Christine said:

“When I asked her what was wrong she said she was really sad about what her teacher did that day. "I want her to be able to express her thoughts and feelings in a healthy way, as children should."

The mum explained that her daughter arrived home upset by what her teacher had told her. She also said that Julie was now "afraid" to have any best friends in her class. When Christine approached the preschool about this issue, she received a letter saying that the term 'best friend' might exclude other children and that they had decided to ban it for this reason. The letter read:

"It has been our experience (which spans decades) that the use of the term 'best friend,' even when used in a loving way, can lead other children to feel excluded (...) which can ultimately lead to the formation of 'cliques' and 'outsiders.'”

So, what do you think of this? Good idea or pointless?