In general the song is about a few writers who were plagued with disillusionment despite or perhaps because of their brilliance.
Brett on "Caringosity killed the Kerouac Cat": "Cat" is a slang word just like "dude" or "guy". Jack Kerouac was a writer from the Beat Generation whom Brett deeply admires. Along with William Burroughs, Allen Ginsberg, and Ken Kesey, they defined the "beat" poetry and literature movement of the 50's and early 60's. After Jack's friend Neal Cassady died, he got so depressed he drank himself to death (although he had his drinking problem long before Neal died -from about 1958 until his death in 1969 he barely wrote and did about a quart of booze a day, plus various other drugs). As the saying goes "Curiosity killed the cat" and caring too much may have been a condition of Kerouacs and so "Caringosity killed the Kerouac cat".
Inspirations
Brett tried to model Stranger Than Fiction after an Elvis Costello kind of song.[1]
Live
Greg used to sing live "I wanna know why Gurewitz cracked, sometimes truth is stranger than fiction" (e.g. 13.9.96 Stone Pony, NJ) and, at least once, he sang "I wanna know, where Brett gets his crack, sometimes truth is stranger than fiction".