In History and Illusion in Politics Raymond Geuss writes that:
A 'human right' is an inherently vacuous conception, and to speak of 'human rights' is a kind of puffery or white magic. (p. 144)His primary complaint seems to be that there is no means to enforce these rights, and perhaps should not be. So to say that everyone has a right to x is to say no more than that it would be good if everyone had x, and yet to imply somehow that one means more than this.
I don't see what's wrong with this though. That is, I don't see what would be wrong with rights talk if all it amounted to was "a moralising conception about what would be desirable" (p. 142); nor do I see what would be wrong with such talk if it were meant to be more than that (but less than the claim that there is an actual, enforceable, legal right), because adding the word 'very' or 'extremely' before 'desirable' would provide the more without introducing any obvious error; nor do I see anything wrong with the allegedly implicit suggestion that we can discover what is so desirable, given that we can discover what is desirable and have discovered (or perhaps remembered) that women and men are equal, for instance, and that their being treated so is desirable; nor do I agree with Geuss that, if rights are a fiction, they are an inconvenient fiction (see p. 147). Rights talk isn't going away, as he recognizes, and whether it does more harm than good surely remains to be seen.
More on this soon, I hope, but Geuss strikes me as better on the idea that rights are a fiction than on the claim that they are a malign fiction. I don't deny that they are a kind of fiction, so it's the malign part that most interests me. He sometimes seems to think the fiction is malign just because it is a fiction, and I don't buy that. He also seems to be thinking of heavy-handed attempts to enforce moral views, which I agree could well be bad, without considering the good that can be done with this kind of rhetoric. (For an example of the kind of thing involving rights-talk that I like see here.) A quick read suggests that there is some old-fashioned positivism in his thinking (rights are either enforceable or mere expressions of moral views), but I'm curious to find out what I might have missed or got wrong.