You could almost say the same thing about those cultural languages though. If me, as a white American, wanted to learn Navajo... what's the point? I'm not Nativ

You could almost say the same thing about those cultural languages though. If me, as a white American, wanted to learn Navajo... what's the point? I'm not Native American, I'm very unlikely to adopt their culture, and my knowing the language isn't really going to further the spread of their culture. So I'd just be learning it as an enthusiast with a quirky hobby and have no one to talk to. The problem with trying to save dying languages is that you need to save their dying culture, too. Otherwise the language is useless, just as useless as Esperanto. If there's no point in Esperanto because it's a language without a culture, there's no point in learning a language without learning their culture. And culture is often a very tricky, very closely guarded thing. What we have with Esperanto is a brand new culture that's been created, one that's a lot more relatable to a wider audience than Kasanga or Iñapari.