With that said, a lot of the problem stems from the fact that a popular author from the "outside" culture is going to have a lot more influence on what others in the outside culture believe/understand about the "inside" culture.
As an example from my community, just about every movie written about transgender people by a cisgender person spends a lot of time showing the subject putting on makeup or wearing heels, implying that the essence of what it means to be a trans woman is wearing makeup or high heeled shoes... But it isn't the case.
That would almost be ok, but the popular movie is going to get a lot more airtime than an indie movie made by a trans person which shows what our real lives are like. In fact, that movie may not get made at all.
So it's worse having the popular movie out there, making money off of our lives, but misrepresenting them at the same time. (And this is all assuming that no harm was intended... it's still harmful, and it happens all the time.)