Changing the label doesn't get rid of the stigma, it can just transfers to the new label. But it can be part of the process of getting people to think about those kind of things, and working towards getting people to see members of an stigmatised group as people first.

And when people who have a label stuck on them indicate that they want that label taken off, to refuse to comply with that is just bloody bad manners.

I strongly suspect that most of the examples of stupid examples of language described as PC were actually originated and promulgated by people who were trying to discredit the concept of using language sensitively so as to avoid hurting other people.

There used to be all kinds of stories in the press about how loony left councils in England were penalising people for asking for black coffee, or were banning nursery rhymes like "Baah Baah Black Sheep". Most of the time the stories were lies, but that didn't stop them spreading and being used as ammunition.

"If in the year 2000 you use the term 'mankind' you are referring only to male members of the human race." Not where I live. We might not say "Man" as a synonym for "Humanity" - but Mankind, no problem. And I think the term "male members" is one to be used with discretion...