Eugene Volokh uses scare quotes to refer to The Vast Right Wing Conspiracy and The Jewish Conspiracy, both of which he then goes on to admit to being a member of (along with most of the contributors to his blog). Scare quotes usually indicate that you believe there's no such thing, and I'm sure that's actually his view. But then he says he's a member of both. This is an interesting set of views.
He must think these terms refer to the groups that Hillary Clinton and anti-semitists (respectively) call by those names, and those groups really exist (because a group is just a group of people), but the groups don't have the features believed to be true of them (among other things, being a conspiracy). If that's right, then he's taking the names as proper names (and not definite descriptions, which wouldn't refer to anything) and taking them refer to exactly the groups the people whose false beliefs generated the existence of those groups (or at least generated their social relevance if the group exists simply because the members exist).
It struck me that this is almost exactly what the majority view in philosophy of race says about races. Races are social kinds whose existence (or at least social relevance if the group exists merely because its members exist) was caused by false beliefs by those doing the classifying. But the difference is that everyone uses race-terms, even those who pretend there aren't any races. Most people, on the other hand, don't believe in either of these so-called conspiracies. That's why his speaking this way sounded funny to me in this case, almost as if it requires saying it tongue-in-cheek.