they're not using liberal in the american sense of liberal meaning gay blue haired woman with pronouns and vegan lattes that conservatives get mad at (in general theres a lot of queer vegan women with pronouns and colourful hair on hexbear); they're defining liberal in the marxist sense in that its people who support capitalism but arent currently fascists, so this includes conservatives, neoliberals, social democrats, and all sorts in it. Their comment seems to be applying more specifically to the ideologically committed liberals as opposed to mostly apolitical people who just say, "oh yeah i guess i;ll vote democrat this time" once every 4 years and have that be the extent of their politcal consciousness