Apparently, the Guardian picked up this story from the Harvard Crimson. Shortly thereafter, the Crimson issued this correction:
The Sept. 29 news story "Scalia Describes 'Dangerous' Trend" misquoted Supreme Court Justice Antonin Scalia as saying that "I even take the position that sexual orgies eliminate social tensions and ought to be encouraged." In fact, Scalia said, "I even accept for the sake of argument that sexual orgies eliminate social tensions and ought to be encouraged."
Scalia has made similar statements, tongue firmly planted in cheek, to make the point that while judges can and do have personal moral judgments, it is not their role to impose them on citizens.