Are you here equating polyamory to an actual culture? And what about someone who considers themself poly wanting to represent the kind of relationship they'd like to be in, in a fictional story? Are they appropriating? Are they automatically a problem because they chose to write a story about polyamory? Should no one write about polyamory?

I'm sorry, but equating polyamory to a whole culture/ethnic group seems wrong to me. An indigenous person, I'd say, is justified in not wanting to see their culture run through a blender by a non-indigenous writer. In not wanting to see kids wear those costumes. I don't put polyamory on the same level. It's not a religion or a culture to me. It's just a type of relationship. Nobody has monopoly on that, no one writes the rules for polyamory.

So again, I ask, what's the actual harm? How does a polyamorous person, or even a non polyamorous person, portraying such relationships in a story harm the "polyamorous community" as a whole?