Indian-American and American Indian are two different things
They're talking about Indian-Indians from India.
It's confusing to describe Native Americans as 'Indians' because that is the only name for people from India.
Yeah, context is key too, as if you're talking about the Indian Reservation it's probably not full of New Delhi migrants. But on the internet (where we perhaps do most of our communicating) the term 'Indian' is confusing to pretty much all non-North Americans. To use the word for both groups makes it too ambiguous.