It's not so much that there are only white lenses there, it's just that you do only see the white lenses because well, they stand out. But, it's true that at sporting events, the majority of lenses are Canon, and I do believe it's because for a while, the digital cameras Canon offered were faster than those Nikon was offering at the same time, and well, once someone is into a system, they generally stay. Nikon is just as popular as Canon to my knowledge. Look at wildlife photographers, Nikon mostly. It's all about what you're shooting.