And maybe - this is a wild guess on my part - Bay didn't want to have an Asian-American US military officer be a bad guy? Maybe he's actually trying to be enlightened.
Uhh, since when was the Shredder a US military officer? He's the leader of a gang of criminal ninjas from Japan. If this movie has reimagined the character to be American, then that's still more ethnocentric than the original no matter what race the actor is.
Besides, it's not as if it's always racist or unenlightened to have villains played by nonwhite actors. If it's an obvious or denigrating stereotype, like Arab terrorists, say, then it can be a problem. But it isn't automatically a problem. The upcoming The Wolverine
features Silver Samurai as a villain, but I don't hear anyone criticizing that as racist. After all, the movie's set in Japan, so it makes sense to have both good guys and bad guys who are Japanese. TMNT has both as well: it's fundamentally driven by the feud between the heroic Hamato Yoshi and the villainous Oroku Saki. It's a story that takes place in New York City but has roots in Japan, and there's nothing wrong with that, because New York City is the most multicultural and cosmopolitan city in the US.
And what's Fichtner supposed to say? "No, thanks, throw oodles of money at some other white dude?"
How about "No thanks, try throwing oodles of money at a non
white dude for a change"?