At least Les Mis is based. Marx writes a few cool things about the Socialist rising of 1832. In the book Enjolras is literally "Robespierre did nothing wrong" and he's the centrist in the Revolutionary group.

Hamilton is really, really awful. But that's what you get when it's a cast of villains.

I assume your lib friend is like conservatives who love RAtM, they just like the chords and the lyrics have no meaning.