Of course anything on social media, which degrades pupils is unacceptable and unprofessional. There is no excuse.
However, one group like this does not mean that all teachers should be tarred with the same brush. There are bad apples in every walk of life.
When I was teaching and IT co-ordinator, despite staff signing an annual statement, agreeing to be responsible and discreet in their social media activity, I discovered a conversation about a challenging pupil on Facebook, on an account which wasn't private. Anyone, including the parents could read the comments.
These professionals were so naive, they even had parents as friends. I spoke to them and advised them to delete the conversation, any similar ones and make their accounts private and informed the HT. They were lucky they didn't lose their jobs over it.
They never spoke to me for ages, until a colleague informed them that I had actually prevented them from losing their jobs.
Not condoning it, but there was no malice involved, they were naive, young teachers, venting their frustration about this violent pupil, who on one occasion stamped on my broken foot, which was in the process of healing. The office staff at the other end of the school heard my screams.
In my thirty years of teaching that was the only time I came across an incident like this.