This may seen like a lot but it's all laid out very straightforwardly in one of a couple books on the topic that you can read in an afternoon, so this is very much a case of the most annoying people you know latching onto something while willfully misunderstanding it
See also the concept of a relationship escalator, which is actually a useful analogy for the assumptions inherent in monogamous relationship progression in american culture, but only really works if you pair it with a staircase, where the steps are taken deliberately based on mutual communication
As to why all the words and definitions, I like many would prefer for relationships to just be something discussed and experienced with the persons involved, but unfortunately american society decided sex and relationships must be highly regimented, so here we are
appreciate the explainer! I had never actually had it broken down and explained as a concept vs an off handed mention (or, often, a punchline)
For further reading, Ethical Slut is.....fine (although not exactly about polyamory per se), Smart Girl's Guide to Polyamory (despite the name) is much better
the reasons are probably as varied as the people involved, but surely for some of them the terminology-chopping is a source of pleasure unto itself. a kink, as it were.
Scheduling is absolutely required to make it work if you're going down that path and also there are definitely people with calendar fetishes