I first heard the term in reference to red tabby cats, do you suppose Ginger cats are offended by the term?
My old roommate’s teenaged daughter found a cat and was allowed to keep it. She named it Ginger. The cat was grey. It was almost a year before she realized that Ginger didn’t mean ‘grey tabby’; I hated disillusioning her, but it just hadn’t occurred to me that she called her Ginger because that’s what colour she thought the cat was. 
I don’t believe this is the case at all. “Ginger” may have become derogatory- if it is- but was not “intended” to be. Dorogotory connotations come with how the word is used and not from the word itself. That is where your analogy with the word “nigger” falls apart as well. As far as I know the n-word was never used in a non-derogatory fashion (modern usage amongst some African-Americans and attempts to “take back the word” notwithstanding) it has always been and was always used for derision.
Ginger describes a sub-set of red-heads that is, all Gingers are red-heads but not all red-heads are Ginger and that is why it is used instead of “red-head”. It is the same way as someone might say “She is a blonde” and it is benign and descriptive, but if you were to say “She is a blonde” with a sneer, then it would become derogatory. If more people are using it with a sneer then eventually we will recognize the word as primarily derogatory and eventually replace it with a more PC term until that becomes derogatory and is replaced and so on…
Derision of red-heads did not start or end with the word “Ginger” and also includes red-heads that are not of the Ginger variety. It has been noted throughout history. Here is a brief bit:
And “Ginger” has been used to define that particular coloration for years (way before my memory). The use of Ginger as derision seems to be a more recent phenomenon (and seems to be predominately in the UK) “Ginger Kids” and “Kick a Ginger Day” aside- that was likely fueled more by South Park than by any real discrimination that came before it.
It is really no different than “retarded” “lame” “gay” or any other word that was once accepted but has been co-opted for an uglier use.
We are not so fond of the IRA, but don’t have a problem with the Irish in general. If anything, I think the attitude toward the Irish is positive, regarding them as being lovable (and sometimes roguish) characters.
I don’t really regard “ginger” as being derogatory either. It is perhaps mock-derogatory, but not really used with any spite, in the same way one could use “blondie” rather than “blonde”.
I always thought the “redheaded stepchild” thing was about redheads supposedly having bad tempers, not being outsiders or unattractive.
So that it rhymes with finger? I’ve never heard it pronounced that way.
Yes, this was the anagram song I was referring to above.
More like it rhymes with “singer” I think.
Well, I could be wrong, of course! 
I remember hearing that there was some association with witchcraft way back in the day. Don’t remember where I heard this, though, so…grain of salt and all that.
When my sister was living in Bristol, she got to discussing Harry Potter characters with her housemates. They told her that according to British boarding school culture, Harry’s friends were basically considered rather at the lower end of the social hierarchy. She pondered this for a bit and then said “well, what about Ron? He seems pretty normal to me.”
They looked at her as though she’d grown a third arm and said “but…he’s a ginger.”
She, of course, was floored, because it made NO SENSE. It’s just HAIR, for fuck’s sake!
It was interesting, though, because it actually explained a few things about the books. When I’d first started reading them, and much was made of the fact that the Weasleys all had red hair, I thought “okay…so??” It was only after I learned about the aforementioned weirdness about red hair that it made sense. It also solidified my opinion that the Weasleys are about the coolest fictional family ever.
Redheads are smarter, more humorous, better looking and more wild in the sack. That makes everyone else jealous and petty.
Redheads, man. If the UK doesn’t want theirs I’ll reluctantly take them off their hands. I’ve always known about the stereotype and discrimination, but it’s always been something I read about, I’ve never seen or known anyone who’s actually ever looked down on them.
I have a friend who’s son is redheaded, and when I called him a ginger (in jest) he thought I was making a Gilligan’s Island reference somehow. Come to think of it, that seems to be the most common thought pattern I’ve come across.
If the likes of Florence Welch and Kate Nash haven’t convinced the British that redheads are beautiful, they’re hopeless.
I’ve not heard that “red-heads” in general aren’t beautiful, in fact just the opposite, despite the claims of witchcraft and vampirism; but neither of those two pictures showed a Ginger. 
Personally I think some Gingers are beautiful, some are average looking and some are ugly…hey! Just like everyone else with other colors of hair and complexion, go figure. 
It really is exactly the same as saying, “S/he’s a Brunette” or “S/he’s a Blonde” or even “S/he’s a red-head” (but Ginger describes a particular shade of red-head and pigmentation). The problem comes when it starts to be used as an insult, much like “dumb blonde” jokes. But we still don’t find “blond/e” itself to be a derogatory term.
However, words do evolve and the more it is used as a pejorative, the more it will become one. It seems like it might be heading that way for the UK folks, but I believe it is mainly still a descriptor here (at least in my social circles) in the States, other than a few isolated incidents sparked by the South Park episode which was wholly misunderstood (it was a metaphor for prejudice, people, not a call to arms against Gingers!) by some more shallow-thinking groups of individuals.
I hadn’t thought of it in those terms, but, yes, in the States we do denigrate blondes in a way we never do redheads.
Discrimination against red-haired people has existed for a very long time.
During the Spanish Inquisition pelorojos were burned at the stake, their red hair an indication that they had been singed by the Devil’s fire.
As far as discrimination against red heads in the States, my son began school in the seventies and at that time his hair was a carroty orange. By second grade he was wearing a baseball cap to school and for years teachers had issues with him not wanting to take it off.
Was the teasing unkind? I don’t think so. But it seems that a brilliant head of red hair is frequently commented upon and the attention made him feel uncomfortable.
This is where it gets a bit dicey. If the teasing wasn’t unkind, then was it really discrimination/derision? I can fully understand the attention making him uncomfortable, and that is an unfortunate side effect of having any striking feature that is difficult to hide or ignore.
Historically yes, there has been much discrimination against red-heads (as I cited several posts back) and I am sure it exists today, but the fact that discrimination exists does not make a word derogatory.
Ginger Minger is a much more offensive term.
I think you mean Fire Crotch, yes?
I didn’t get called Fire Crotch, or “FC”, until I was in my late 20’s. It was in sort of an odd context; I don’t know whether it was supposed to be an insult or a come-on. Sadly, being married already, I couldn’t explore the situation further. Typically, though, yeah, it’s more offensive to me than any of the other red-headed epithets, which really don’t bother me at all.