I was surprised when I heard about gingerism a few years ago. I had no idea that it was a thing... because it really isn't a thing, as far as I know, in the United States. We Americans have invented enough reasons to hate and bully each other without throwing hair color into the mix.
(Says the woman who endured a few dumb blonde jokes a few months ago, then lost her boyfriend when she became a brunette again. You know, now that I think about it...)