Perhaps. You missed my point. I agree you are right...but only in some case. Not everyone is the most objective observer of their own life, and thus, if someone hearing the life-story of another wants an objective re-telling of it, perhaps in some instances another person could do it better.
To use another example to illustrate my point. Michael Jackson. Let's presume everyone reading this (like, 3 people) agrees he molested children. Ok, do you think Michael Jackson is going to oversee a film that includes those aspects of his life? Or even those nearest and dearest to him? Sure, you could stay this is an extreme example, but the rationale still sticks because it's broadly applicable.
The point is, Lang Lang could be right. Perhaps someone else closer to the context could do a better job than Ron Howard at telling the story. 'Perhaps', 'could' - key words. But let's face it, she does not know it to be a fact (despite what she may think), and nor do you. The problem with what she has reportedly said is that it's based purely on Howard's own race/ethnicity. She's making a presumption that he could not tell the story better than someone from that region....because of his race. That's racist, and as you say, that's a fact. It's also a fact there's an irony in all of this that where (I presume) she's coming from is a desire to overcome historical prejudices against non-whites in the film industry....by being prejudiced herself. Oh. The. Irony.
Ang Lee - first filmmaker I thought of! By her rationale, he should not have been allowed (keyword right there) to make Brokeback Mountain. And what hatchet job he did! Terrible execution, very inauthentic, grossly misrepresented the people in it, nobody saw it, everyone unanimously agreed it was terrible, and didn't get a look in at a single awards show....
Let's face it, she's basically being racist. Like, we all get where she's coming from and why....but...ya know...the grounds for what she's calling for stems from Howard's race/ethnicity. *shrug emoji goes here*
Not to mention, sometimes those "on the inside" aren't the most objective observers. Using football as an example - or any major team sport really - the players, whether current or past, aren't necessarily the best at explaining what has happened and why. Sure, many are. But there are plenty of people who never even got close to "the big leagues", but had an enormous interest and love for the subject, that go on to understand "the game" (not just what happens on a field/pitch/court, but also everything surrounding it/in that world) far better (and sometimes more objectively) than those "who were in it, man".