There are two worldviews that I believe are in general bad for humanity. Obviously, one of those things is "religion" as you could probably tell from the allusion to Christopher Hitchens' book God Is Not Great. But there is another worldview that permeates through society and that is a very bad thing: this view is called "postmodernism".
These two viewpoints are in many ways opposites. religion --or at least fundamentalist religion-- states that we already know the absolute truth. Postmodernism states that there is in fact, no truth at all, and that all "truths" are equally valid, inc. moral truth. Religion induces by its nature disdain for those infidels that will burn in hell, whereas postmodernism is a misguided attempt to include everyone. Fundamentalist religion is the rallying cry of the relatively uneducated right; postmodernism that of the academic left(of course, I generalise).
Why do people embrace postmodernism? It probably stems from the liberal belief that all people should be seen as equals. Unfortunately embracing all cultures as equal means that one cannot embrace all people as equal(by definition)--for example a society where women are treated awfully(eg, Saudi Arabia) is equal to a modern democracy where they have equal rights. (This argument would apply even if the misogynistic cultures were fictitious.) Of course, this is a big problem because it prevents people distinguishing between moral action and immoral action, and it encourages people not to criticise bad culture. It also promotes the idea that if something is cultural it's somehow sacred.
Postmodernists also often criticise Western culture. Of course, there are flaws in Western culture, but for a pomo to criticise it is hypocritical(if all culture is equal that includes the West.) They often talk favourably of more tribal cultures, even though to be frank they are much more immoral than Western culture in many ways. For example, in the Jivaro tribe up to 60% of the males die in warfare; it is about 40% for the Yanamamo. For Britain and Europe 20C it's about 2 percent, and that includes WWI and WWII!*
As for more general truth, well, let's face it, science works. Yes, I am perfectly aware of things like the problem of induction, but philosophical problems with science do not suddenly make all truth equal. I mean, even if there is no way we can get at absolute truth, that doesn't mean that absolute truth doesn't exist, and scientific evidence suggests that there is truth, eg gravity hasn't been proven wrong yet. And some "truths"(in the pomo sense) are backed up by evidence, and some are not. If truth was relative, why isn't there some evidence for every hypothesis?(Okay, you might want to say that we might not be able to always get at that truth. But science seems highly successful as demonstrating at least some "truths"(eg gravity) and not others...why would the scientific method only work for one type of "truth" and not others?)
Even pomos do accept science, even if they don't want to admit it. Pomos don't jump out of a window because the belief that they may fly like superman is not equal to the belief that they will go splat. Pomos don't attend a shamanic healing because the belief that shamanic healing works in not equal to the belief that scientific medicine(generally) works. Etcetera.
I believe religion and pomo to be both views that are too extreme: religion's claim that we know all the (important) truth is too strong, but pomo's claim that there is no truth is far too strongly in the opposite direction. In truth, our position is more in the middle. We know a lot, and we don't know a lot, also. I'm aware that all the truths we have now may turn out to be wrong, but this does not, of course, validate postmodernism.
* Statistics from Pinker, S. The Blank Slate, Penguin Books 2002, p. 57 (it's a bar graph, thus readings may not be 100% accurate).