@kdt26417 - well-written!
I think I need to highlight what is to me the major point you are making - we are trying to get the concept of multiple simultaneous romantic/sexual relationships to be accepted by society as a valid and healthy for of relationship, not the word "polyamory".
Redefining the word thus doesn't go any distance towards getting anything that I would suggest we really care about accepted.
"Listen, or your tongue will make you deaf." - Native American Proverb