Turkeys have SUPERB color vision.
The reason you shouldn't wear red, blue, white or black (gee, that leaves SO MUCH in the average outdoor wardrobe) in the woods during turkey season is that it is the most dangerous hunting season of the year (at least in this state).
More people shot "mistaken for game" than any other season. Not all of them other hunters.
I wear tons of blaze orange all May, as do my dogs (two of them mostly black, one that looks like a giant coyote, another one coyote-colored).
Now, I like wild turkey as much as the next guy, and I do hunt them (without much success, mostly due to lack of time and obsessive focus) -- I cannot fathom getting so het up about bagging a fifteen-pound bird that I'd get an itchy finger and fill a hiker or a Labrador with turkey shot.
Yet it seems to happen pretty regularly.