As Ben Shapiro popularized, a “snowflake” is someone who melts when confronted with an opinion or fact that is inconsistent with his or her worldview.
Karl Marx was a snowflake. For proof, look at how he refused in The Communist Manifesto to respond to charges against communism from three standpoints:
The charges against communism made from a religious, a philosophical and, generally, from an ideological standpoint, are not deserving of serious examination.
Signet Classics edition of The Communist Manifesto, by Karl Marx and Friedrich Engels, with an Introduction by Martin Malia and a New Afterword by Stephen Kotkin, p 90