In this excerpt, the speaker questions why someone refers to a person as M. d'Harcourt, while another individual is simply called Jerott. The implication is that the name M. d'Harcourt carries a certain respect or formality that isn't applied to Jerott.
The speaker then admits to having used harsher or more insulting terms for Jerott, suggesting a familiarity that allows for such language. The contrast highlights different levels of respect or familiarity in their relationships with these characters.