Trying to jerk the thread back to its original topic (though I'm gonna fail due to the example I'll cite):
Many times the old representation is rejected because it is a horrible stereotype, or because it became loaded with negative connotations over the course of its time in popular use. These are excellent ways to drive people away from using the word or image. On the other hand, it is often the case that the old term or image is not actually offensive, but is merely less accurately descriptive than the new word. An example is the "many names for black people" that was brought up earlier in this thread, where most of the names aren't even offensive, just archaic, and every transition was a natural transformation of language in the context of its times.
Despite the arguments of those who would rail against it, political correctness is not the doing of a hostile censor or cabal of oversensitive reformers. The very concept of political correctness as a looming social pressure calls to mind some kind of vast left-wing conspiracy. But in reality, political correctness is a very modest thing -- it is the ebb and flow of social trends, the silent and gradual transformation of language and images. Political correctness is a pejorative euphemism for modern expressions that have supplanted older ones. It's what grownups use to complain about the steady evolution of modern slang.
And yes, the result is almost always for the better.
Here's the thing: you're describing PC language as if it was a natural phenomena, whereby people hear a neologism and adopt it into their idiolect without explicit outside influence. As a general rule, that's not how it works. There is a definite prescriptive tendency in PC language development; a neologism is coined, and its users actively attempt to supplant the current term with the new one. This differs from slang proliferation in so far as slang tends to be more frequently spread by passive means (someone hears it, and decides to add it to their idiolect) rather than by active means (a speaker attempts to influence others to add the term to their idiolect, generally by replacing an older term). There is also another difference in terms of how social pressure is applied to encourage conformity; failure to adopt a PC neologism is generally greeted with an explicit or implicit expression of moral judgment, whereas failure to keep one's slang up to the minute will be faced with social disapproval of their failure to conform, but their motives for doing so will not be impugned.
Having said this, I actually tend to be sympathetic to PC language trends, and have upon occasion played PC police by attacking terms loaded with horrible connotations and less accurately descriptive than the newer word. An example (emphasis added):
I don't want to ban homophobic language. You are legally entitled to use it. But know that if you use homophobic language, I will think less of you.
Here we have a nasty, archaic term that by all rights should be consigned to the linguistic dustbin of history, and supplanted by e.g. heteronormative.
"Homophobic" was coined with the
explicit intent of suggesting that those it labeled suffered from a psychological disorder. I've very frequently seen it used in exactly this light, and those on the receiving end of the epithet often respond with the assumption that this is the intended meaning. Indeed, the last time I got into an argument over this term, on a 3rd-wave feminist blog where an anti-same-sex-marriage screed by Orson Scott Card was being eviscerated, one of the term's principle defenders was eventually pinned down to an admission that they preferred this term to the alternative foremost because it was viewed as highly insulting by the targets. Additionally, the term can be intended or perceived as a bludgeon to belittle the target as being a coward, to accuse them of being
afraid of homosexuality. I think it's safe to say "homophobic" is loaded with negative connotations. Very much by design, in point of fact.
It's also less accurate than "heteronormative". Again, the term was coined to suggest its target was mentally unstable. Not that they held wrongheaded, evil ideas, but that they suffered from a pathological mental illness (the term was coined by an activist as a mirror to the APA classification of homosexuality in those terms; the APA ceased classifying homosexuality as such with 1-2 years of the term's coining, but "homophobia" lived on, obviously). Some people still use it as such. Some people, when it is applied to them, still take it as such. It is also used at times as an accusation of cowardice. Not as a denotation of prejudice against homosexuality, but rather as unthinking, uncomprehending fear of it. This will often result in the waters of a conversation being muddied by the target responding angrily that they're not afraid of homosexuality, they instead find it immoral or whatever (it was OSC's multi-paragraph insistence upon this point, that he
couldn't be accused of homophobia because he had perfectly rational reasons for denying civil rights to homosexuals, that led to the aforementioned argument over the appropriateness and utility of the term).
Heteronormative, by contrast, is much clearer in what it denotes: "Of or pertaining to the practices and institutions that legitimize and privilege heterosexuality, heterosexual relationships, and traditional gender roles as fundamental and 'natural' within society"
1. This is cleaner and less ambiguous. It is less likely that the target of the term will misunderstand what it means. The term is more neutral and focused on a structural level, making it less of a normative term and more of a positive description; it is unambiguously about bias and antipathy, not fear.
However, those fond of "homophobe" for its pejorative connotations will resist changing to a less archaic, ambiguous term - but so will those who view the older term as innocuous and unambiguous, as well as those who view the attempt to replace the term as a needless intrusion by bothersome hypersensitive meddlers who should be resisted on principle.