To me this song is a rather scathing commentary on the Christian religion. Particle Man was pagan humanity, each person managing their own relationship with the divine. Triangle Man represents the Father, Son and Holy Ghost the Christians are always talking about: they hate Pagans. Universe Man represents Zenists of all types, Buddhists, Taoists, etc - everyone's happy around Universe Man. Person Man represents modern humanity, faced with preexisting religious views competing for their advocacy, made to feel inadequate by many religions and struggling to just survive. Notice the Traingle Man hates everyone and always wins - the state of Christian religion in today's western world.