I think that Butler, Brown, etc. got their targets wrong, and I also think that the battle they chose (what kind of epistemology do we need?) is not of primary importance, but I do think that there is such a thing as left conservativism. In my terminology, left conservatives possess the following characteristics:
(1) economically populist but socially conservative;
(2) think that anti-sexism, anti-racism, anti-heterosexism, etc. are divisive and must be subordinated or postponed;
(3) while economy is a materialist question, gender, race, sexuality, etc. are not.