Supporting Excellent Iraq War II, pumping the _Bell Curve_, publishing the racist fantasies of Stephen Glass, joining the anti-public education movement, and also publishing the "No Exit" hatchet job on Bill Clinton's health care reform proposal isn't in any way shape or form liberal. And that's not even taking into account Martin Perez' racism and ethnic hatred which is of a variety that is a bit harder to criticize in US society but which most liberals reject.
Representative quote from Andrew Sullivan: "The middle part of the country—the great red zone that voted for Bush—is clearly ready for war. The decadent Left in its enclaves on the coasts is not dead—and may well mount what amounts to a fifth column." [note that he later altered that essay as published on his blog to make it less self-damning; this is the original wording]. Yes, he's gay. No, he's not liberal.