The black hood was a common feature of the cars built for racing in the various circuits, which often had a requirement of a certain number of vehicles being manufactured for public sale as well. This was how we ended up with the Boss 302 and 429, the Camaro Z28, Trans Am, AAR cuda's, Daytonas, Superbirds, etc. The hoods were often painted flat black to prevent glare. Why they didn't do this with all the race cars back then, and why they don't don't do it today is most likely because it made little difference, there would be enough glare coming up off the pavement that the black hood wouldn't help. I think it's a cool look and harkens back to the days of true muscle car styling. Ricers often have carbon fiber or unpainted hoods, which is different, and I agree any unpainted piece of body kit you just slap on your car looks pretty stupid. If you can't afford to paint something that is purely for appearance sake, then don't bother buying it and putting on your car.