It`s actually for simplicity sake, for me.
I have the ability to love more then one.
I don`t have the ability to carry out polyamorous relationships, as defined by the majority who engage in polyamory. What the majority believes as 'ethical' is not what I believe.
So rather then split hairs, or bowl everyone over to my way of thinking, I just don't identify. Keeps it simple, and stops many wanting that style of life, from hoping I`ll be what they desire.
( Do all poly people think the same way ? noooooo, I am sure there are some who view things as I do, but for simplicity sake, I let majority rule. The label just doesn`t mean that much to me. )