Panspermia doesn't necessarily rule out some intelligent agency for its propogation, but neither does it depend on one. That only applies to desperate creationist-style arguments.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'