This is the first time I've been introduced to Girard's theories. I don't agree with a lot of his claims but I think he (and others; his theories aren't entirely novel) definitely stumbled upon a real aspect of humanity.

I suspect the real "truth" is a greater superset theory that encompasses some of these theories and also unrelated theories and observations, though. Girard espouses a lot of absolute claims ("all human behavior is mimetic") while discounting other potential factors and certain counter-examples.