Teachers, parents, friends and others in referential positions without realizing , often negatively label people.
You are a woman, you can't drive ... you are dark, you can't speak English so well, you are from North India you must be aggressive, you are a marwadi - you must be stingy, you are a Gujju - you must be manipulative, you are a woman - how can you be a good Engineer ??
NEGATIVE LABELS badly impact achievements. Often unknowingly, parents, teachers, friends, relatives and others label people they transact with. My very dear (and absolutely honest) friend suffered trust issues because she had 'cat -eyes'. No one would immediately trust her for strange reasons. And she never realised it till late. Those who have not been labeled, will not realise how deep this issue can become unless you are one of those in the marginalized sterio-typed groups who suffer it.
This however also doesn't happen to everyone in that group. It happens to those with fixed mind-sets. Those in that group with growth mind-sets break through the group typography and prove their worth. Growth mind-set takes the teeth out of such sterio-types.
Unless you are mean and are determined to be cruel to others, don't negatively label people. You will do a massive harm to people for which you may repent later when you realise.
Remember, when you label people regularly, you could also easily fit into a negative counter label - 'unfairly judgmental' ! And this you may not like as a leader if it spreads by word of mouth.