Marxist humanism is a very liberal (in American way) interpretation of the work of Karl Marx, especially the Paris Manuscript and his early theory of alienation.
Most of the authors whose books inspired liberal 1968 student revolt self-described themselves as Marxist humanists, e.g. Herbert Marcuse or Wilhelm Reich
Also, some liberal feminist movements are inspired by the unfinished book of Karl Marx published by Engels. The Origin of the Family, Private Property and the State
Marxism attempts to liberate people from work, culture, religion, and morality therefore it is a liberal ideology.
