That might help you get it.
1. If the Indian nation and the US has a treaty covering "copyrights" and other intellectual property
It might be why they tried this case in an Indian court first:
A tribal judge threw the original case out of tribal court in 1994
But if you are going to have treaties that cover mundane things like intellectual property, you are probably going to have treaties that cover reciprocal taxation, fair cost of defense and such...
That might help you get it.
The treaties I was refering to were the ones that you seem to deride that gave the Indians the right to do certain things in their own "nation" as you call it. It has nothing to do with copyrights.
I get it, you seem confused. I'm guessing you will never get it and I'm not interested in chasing my tail. Have fun.