Title says it all.
Interesting question, so I’ll bump it.
Have you ever seen the color of ginger root (cooked)? 
Isn’t that more yellowish…?
Because we can’t all be called “Amber”
Dried, powdered ginger does, IMO, have a reddish tinge; as does the root itself. Doesn’t matter so much what you or I perceive the color to be – the word definitely derives from somebody’s idea that the color of someone’s hair was “ginger-y”, and the name took, based in fact or not.
The ginger root I’ve seen is medium brown, with a yellowish tint to the pulp. Powdered has a little red in it. But red hair is usually orange, IMO.
I think it’s like goldfish, which are orange; or red onions, which are purple; or white wine which is light yellowish-green…:smack:
I rest my case…
Powdered ginger can be rather orange. And people who are called “ginger” don’t necessarily have bright red/orange hair; often it is a light orange-brown color, like powdered ginger.
Hijack: What is the point of bumping a thread a mere ten minutes after it’s been opened? What does it accomplish?
I thought they were called “Blue”. 
They are (or were – it’s a bit old-fashioned) in Australia. I suspect that’s being ironic, by choosing the opposite colour in the spectrum from that of red hair.
I never heard “ginger” used in that context until I saw it on South Park. And I’m one of 3 red-haired brothers.
Orange cats are sometimes called “ginger”, something I hear in the UK quite a bit. Sadly, they taste neither like orange nor ginger.
That’s because your not putting the right stuff in their feed.
Because they don’t want to be called “The Professor” or “Mary Ann”
(Or – worse yet – “The Rest”)
More to the point… why is having red hair considered a bad thing in the UK? The term “Ginger” seems to be considered a slur. The use of the term in any context is rare in the US, and never as an insult.
Obviously you haven’t seen the above mentioned episode of South Park!
As an aside, I too had never heard the term until I saw that episode.
It’s the Doper way of complimenting the OP on a good question.
I think Scarlett sneeringly refers to her second husband, Frank, as “ginger whiskers” in Gone With the Wind (the book; don’t recall her saying it in the movie). I think that’s the only reference I’ve ever seen. It must be passing out of use?
The first time I noticed it was in the last Harry Potter book, “Ditch Ginger, and come have a drink with us…”
Why is this considered an insult, though? Sort of just refering to someone in the generic sense?