Attention: I'm not a teacher.
There is my 2 cents contribution. Please excuse me if you left with the impression that some things were mentioned above yet. There are also some more example concerning the matter in question. One of them give you answer your question” How did it come to be a way to "label?”
Pigeonholing is a term used to describe processes that attempt to classify disparate entities into a small number of categories (usually, mutually exclusive ones).
The expression usually carries connotations of criticism, implying that the classification scheme referred to does not adequately reflect the entities being sorted, or that it is based on stereotypes.
Other meanings include when a congressional committees that deal with new bills introduced in the United States congress decide to ignore a new bill, the term "pigeonholing" is used.
Pigeonhole principle = (mathematics) The principle, that if a very large set of elements is partitioned into a small number of blocks, then at least one block contains a rather large number of elements. Also known as Dirichlet drawer principle.
The pigeonhole principle often arises in computer science. For example, collisions are inevitable in a hash table because the number of possible keys exceeds the number of indices in the array.
They played upon her penchant for pigeonholing house guests into their appropriate social categories.
This of course is not true, but those who try to escape the pigeonholing with work that is stylishly individual are labelled "young designer”.
It's proved a good way of picking up and pigeonholing the plight of the young middle classes living in a country in retreat.
All we'd of done was taken pigeonholes and go to them and say don't want that.
There were empty arched pigeonholes at the back, fretted and carved, and two empty little drawers.
She left a series of notes in my pigeonhole that started off plaintively: I'm very confused by what happened between us.
The following morning, in her pigeonhole at the theatre, had been a sealed envelope.
No-one ever really tries to pigeonhole him, because he's a truly talented person.
So I think that the sexual politics in the film is very difficult to pigeonhole.