Why are americans so infatuated with blonde hair?

I am brazilian and half of my family are blondes that's because we have lots of europeans influences as for the brunettes from the european latin origins just like in the US! Not long ago, I had a dinner with some of my husband friends and this lady asked me how come I was blonde if I ws brazilian...LOL...Oh my, I was surprised with her question. I lived in Ohio with my husdand for 10 month and we heard that all the women there dye their hair blonde, even the children, which I didn't believe but them I presence it happen not once but many, the kid was young as 5 years old! My best friend is a sales executive for revlon and he said that US is quotes the #1 country for color their hair blonde (fake blondes) What is all this about? I am going to beauty school and there is no a way I will dye a child's hair, what is all this "blonde" about?