Yes it is! I can understand a commendation for those who have improved a great deal but the other way round is just nasty. We have a tea party with the HT every half term for the 2 children from each year who have improved significantly.
Seems an odd thing to do from a teacher who's under pressure to make all her class move on two sublevels a year. She's trying naming, shaming and peer pressure in a very clumsy way. Apart from complaining about her strategy, I'd want to know what individual targets and support she's told the children will be given to change an unsatisfactory situation. OK to set a goal for the ones not making progress, but she needs to plan and share how they can achieve it.