[thiagoharry]

Class is a very useful concept to understand societies. It's not even an exclusively Marxist concept. Weber also uses the term, but uses different metrics than Marx to distinguish between classes. How can you effectively have a good understanding of feudal society without understanding the division between feudal lords and serfs. Or between citizens, outsiders and slaves in classical Greek societies?

In discussions about philosophy ans philosophical concepts, one do not need to agree with all the interlocutor's assumptions: it is just required to understand them and discuss them in a balanced way.