I'm not sure it's "blaming" unrequited love on Cathar ideology as much as it is holding up how the "tragic love story" was used to continue to transmit Cathar ideas while these days the "tragic love story" exists for itself alone. To me, it's a commentary on the emptiness of something that used to have meaning because, essentially, everything in modern society seems to be about stripping away traditional meaning and inserting your own.