I should also mention, partially because I apparently can't rant enough about the topic, that this phenomenon can be extended beyond the already fairly nebulous and reactionary concept of "The PC Brigade" and into popular perception in general. Arguing about science (and particularly about global warming and second-hand smoking, for example) immediately gets you into the same territory. Discredited theories and "experts" in the pay of oil companies are wheeled out again and again, their vast outnumbering in the academic world dismissed as an international conspiracy by the governments of pretty much every developed nation (including the US at this point, after the Pentagon woke up one day and realised all the troop procurement in the world is of limited use in fighting the Sun) to pretend the problem exists as an excuse to raise taxes. Such minor details as the fact that the international community can never agree on anything (upto and including whether genocide is worth worrying about) and that the Bush administration is the only US administration in history to cut taxes in the middle of a war, which makes them ludicrously tax-hostile even by American standards, and yet it is still now, somewhat belatedly, confessing to the dangers (it's promised to lead the world in fighting climate change, which is nice, I'm pretty sure the rest of us just headed off at random in the direction of lets-not-entirely-fuck-our-own-planet, so it'll be really sweet to have them holding the compass from fifty miles back), apparently don't register. Conventional scientific thinking must be challenged (I made some points last week as to what I think part of that idea springs from), and if anyone disagrees, we must be attempting to silence them, as oppose to requesting that they back-up their shit-talking. Really, it's a neat rhetorical trick. Choose a position a priori, (we have no adverse effect on the environment) listen only to those who already agree with you (helped by the media of course, who seem unable or unwilling to not use the label "some experts" when what they mean is "a tiny minority of researchers and academics with frequently suspect incomes and theories that are invariably shot full of holes"; you could strain peas with Svensmark/Friis-Christensen), strip arguments of context and flense trends from proportion and present them as fact or as common knowledge ("Mars is warming!" "This is the same thing that happened in the Middle Ages"), and then refuse to participate in any attempt to challenge your opinions, demanding repeatedly that it is your right to hold them. I wonder if there's anyone out there convinced blacks are responsible for causing global warming. It would be oddly amusing to discover that this imbecilic arc of douche-baggery has in some sense come full circle.
Update: Not to extend this already ridiculously long post, but it struck me that I should probably make it clear that the latter half of the above diatribe should not be taken as an indication that I consider scientific theory to be unassailable. I'm as aware as anyone else of the voyage of the Beagle. My point is that there seems to be a common misconception that it is someone anyone can do, irrespective of intelligence, talent or, and this is the real one I have trouble with, of knowledge. And just deciding you don't agree with a given theory and finding links to other people that don't agree either isn't research, and if you think it is you need to shut up because adults are talking.
I'm also not suggesting that no-one should have an opinion on scientific proclamations unless they immerse themselves in the details. Certainly some pronouncements from the ivory tower seem more plausible than others (of course, unless it's probability theory or maybe statistics I'll be viewing the discussion through the lens of the media like everyone else). Sometimes I'll read a theory and think "That makes perfect sense" (much of The Blind Watchmaker falls into that bracket, I really do wish Dawkins had stuck to defending evolution instead of attacking religion); Sometimes I read a theory and think "That's pretty hard to swallow, I wonder what the evidence looks like?" I can't possibly fault others who tend to fall in the latter camp more often than I do.
But here's the kicker. If you read over your cornflakes that scientists think bacteria has a role in shaping the weather, and you don't believe it, I don't care, because your opinion makes no difference. If, like me, you don't smoke, and you don't buy into the existance of passive smoking, then I don't care, because the worst you can do with that bit of (incorrect) thinking is manage to do your own lungs some damage.
If you don't by into the arguments regarding climate change, then it's my problem. And everybody else's too. If a theory is developed that suggests your behaviour could be harmful to others, it becomes your responsibility to investigate whether it is genuinely true or not. You no longer get to shrug your shoulders and say "I'm not convinced", because what you're saying at that point is "Until I can be convinced 100% that I am harming others, I will assume I am not". And that's a pretty cavalier attitude to the planet (not least because whenever I meet people who tell me they aren't convinced, they are completely unable to tell me under what circumstances they would be convinced). These things don't exist in a vacuum, the more people resist change, the easier it gets for change to be resisted, and at the forefront of that particular battle aren't the people who may actually believe climate change is real but lie about it for profit, but the people who aren't sure and don't want to be sure because it will make their lives harder.
It is, in short, the easy way out. And you should always be suspicious of the easy way out. You can, I guess, point out that there is so much going on in the world that some of this stuff just has to go on the back-burner, and that sometimes if you worry about everything you end up powerless (one example I read a little while ago was choosing between African grown and locally grown fruit, since choosing the latter goes against the spirit of Fair Trade but the latter has a much larger carbon footprint); I tend to think of this as the Wotan Principle. And at least that's honest. But to pretend that the scientific community has failed to convince you and that somehow the fault lies with them is just baldly dishonest.