Critical theory was invented by the Frankfurt School, which wanted to theorize about society and culture, inspired by Marx’s methods in Das Kapital. Its foundations are therefore Marxian.

Postmodernism isn’t Marxist per-se, but many postmodern thinkers have a Marxian influence in their ideological lineage (e.g. Foucault wasn’t Marxist but he had Marxist mentors), plus postmodern critical theory’s focus on power is inspired by Marxist critical theory.

Both critical theory and postmodernism are against liberal values because in liberalism, justice is due to individuals, not to groups or classes. Liberalism is incompatible with class-based claims to justice, that’s why SJWs are illiberal.

Where am I wrong here?