This a good point and one that IMO is lost on a lot of the newer designs. Especially in lieu of these forsaken noses rolling out now. For instance take the new Macca. I find the front wing supports to be very ugly looking and I my gaze is instantly drawn to them. So I would have them (and a portion of the nose itself) painted black to mask out a sharp and aggressive pewter nose to draw the eye to... instead of it's protuberances. The Lotus nose is even more horrendous in my view but because it's not bright and shiny, you don't notice it as much. But hey, that's just me.
Is this a joke (I can never tell with you and that's what I thought when I first read it) or do you mean just in the last 10 years or so? Because there have been plenty with black wings. In the 80's and 90's it was practically de rigueur for Ferrari. I know my second fave (and arguably the most beautiful of the modern era) F1 car of all time, the F640, has completely black wings. If it's just lately to which you refer, then I have no idea if there is a reason behind it.