I work in the school system and have witnessed behavior in adults, especially recently, that stuns and upsets me. Never assume that teachers behave differently from other adults you know. For every excellent teacher, there is one who is immature and petty.
You have friends you trust and friends who love to gossip and pick others apart. Some teachers discuss students the same way, although they aren't supposed to. Those same teachers treat their colleagues poorly also. Cliques within a school and/or district are often emotionally crippling to employees and disturbingly similar to high school cliques.
Our children spend a large portion of their childhoods attending school--their teachers are often a huge influence in their lives. It's too easy to overhear and believe gossip, or to look at a child who has difficulties in class and decide that he/she is a problem. Children who are struggling are reaching out for help--if teachers/schools label them, they may have no where else to turn.
It's our responsibility to learn all the facts before passing judgment. There are always two sides to every story, and often there's validity in both. Blindly following someone's lead demeans your own ability to think things through. Get to know your child's teacher(s), beware of gossiping with other parents--how would you feel if your child was the target?
Be a child advocate--you are the adult, and you have resources and strengths that children lack. Make teachers and administrators in your children's schools accountable for their actions. No one deserves to be a target because they're different from the status quo, especially not a child.