Yes there is a debate still raging over this. Interesting that the eyewitness at Le Shima in the article quotes it as green, so for me the question is this: Was he informed previous to their landing how they were going to be painted? Seems unlikely to this arm-chair general, but who knows how scuttlebutt was passed. And the second question is: Could pre-knowledge of how the "should" have been painted, prejudgest him against what he actually saw? O's Razor, the simplest answer to me is the film has aged to give the appearance of black, but that the crosses where infact green, or there abouts.
One interesting note: I always painted the anti-glare strip infront of US WWII fighters black, when in fact they were mostly olive drab!