He probably gets the character very much. But you know...it being a film, and comics being comics...and he didn't want to throw up a racist Chinese guy on screen to a film that is going to be sold and marketed to China.
You don't need to go the racist characture angle for the mandarin to work.
And you can STILL make him asian.
Some people happen to have an obsession with history. Particularly the history of their own culture.
We had an alien invasion in the Avengers.
We established Magic is nothing but Advanced as hell science with Thor.
New Character take on the Mandarin.
Asian-American guy. Computer programmer who works for SETI. Gets picked on a little becuase of his love of chinese history. And when I say Love, i mean borderline Obsession. Everyone has they guy at work who's cubical is covered with Transformers, or Cars, or Star Wars, or whatever it is they're really into? That guy, but with Chinese history.
Take it a step farther, perhaps he gets snubbed Like killian does at the begenning of Iron Man 3, INSTEAD of killian
Fast Forward. he's now a Computer Tech at Seti, moving on.
Right place at that right time during the Invasion in New york, he sees the equipment he's working on detect something crash in the nearby desert. Why dose no one else see it? They're too busy with the events in New york, and the machine he is working on is broken anyways.
So he gets his car and drives out to the crash site, and finds the wreckage of an alien ship.... picks at it, prods at it.. .and finds the rings. Plugged into the ship, being used as a power supply, orweapons control, or whatever.
He takes them, messes with them, learns to use them.
Power Corrupts, one thing leads to another, we Get a fresh spin on the Mandarin, that has the trappings people expected, whitout seeming too "racist".