The thing is, he's sort of right. Capitalism was defined by its detractors describing what was around them. You can absolutely be against the current order of things, whether you describe it under a term "capitalism" or not.
Yes, capitalism existed for a few centuries before it was actually defined (with the word, e.g. Adam Smith doesn't mention Capitalism). I am not disputing that.
A lot of people seem to discount the notion that ideologies can just kind of gradually emerge as a matter of material conditions instead of being actively hashed out for some reason. It's weird