An author should be able to write about whatever he or she wants. <br />
What I would care about was whether or not it was factually correct or whether it accurately reflected the group about which he or she was writing.
It depends on how much research the author has done on it and how much the author has actually had contact to the ethnic group. But just to write a book with a biased opinion to spread more bad rumours about certain ethnic groups I find is a not a good idea. This is one reason so many people get the wrong impression of certain cultures because they have read things written by "outsiders" who don't really know the true traditions and reasoning behind that culture. They see everything only at face value and don't look into the why's and wherefores of any particular tradition, culture or belief.
It wouldn't matter at all as long as the author knew what he or she was talking about
No, it doesn't matter if the writer knows what they're doing, can tell a story well and has insights into the culture that would resonate with those within.
hell NO ... as long as he doesn´t publish it ... lol
If he used a lot of resources or at least lived there for a considerable time then he may be able to do it. He may not know a lot of things though and may miss some important details.