What does my race/ethnicity have to do with Olympics?

Sorry if I am just a thick-headed Canadian farm boy but I saw something today that I have to ask about. I went to register for tickets for the 2010 London Olympics when I found this question posed to me:

Ethnicity: (it is on this web page)

Two immediate thoughts came out of this. First I wondered how to classify myself. Although I have relatively white skin, I do read books from other cultures and try to live some of their ideals. Buddhism is a particularly large influence on my private thoughts although most of you would never guess it. As I pondered this though the bigger picture entered my head and I asked the first question I should have.

What does your race have to do with watching the Olympics?
Sorry Olympics organizers but I really do not see the connection here. This could not have been asked in Canada at the recent 2010 games during the registration process as every person in Canada is afforded the same quality of life. The Charter of Rights and Freedom’s guarantee';s this in section 15.1 (read here)
15. (1) Every individual is equal before and under the law and has the right to the equal protection and equal benefit of the law without discrimination and, in particular, without discrimination based on race, national or ethnic origin, colour, religion, sex, age or mental or physical disability.”

I guess I am missing something here. Can anyone shed some light on this?