One of the ways that stifling debate on such matters does harm, is that it sure makes it look like kooky opinions like James Watson's or Charles Murray's (seriously, if you don't think Murray is a kook, take a look at his work on "<i>Human Achievement</i>" and the purported measurement thereof - which is of course hopelessly biased to favor Europe and the West) have a lot more currency and more basis in science than they actually do.