Because I have seen it in a code and the code works. The code have the flowing structure:
There is an Entity named A, with a relation with entity B. The relation is OneToMany using a Join Table and the Owner in the relation is the Entity A. B is an Entity with predefined inserts, so its only used for reference in relations.
So, when there are creating a new Object A for persist it, they don't use find or reference for get a reference of an entity B and add it to the list, instead they create new Object of B, assing its a primary key and add the new Object B to the List that Belong to the Object A. And the code works and i don't understand why its work.