Almost certain they were referencing the early Mormons in this episode… I’ve a vague recollection of their first settlement being in Pittsburgh which your man in the show said they had originally settled in but fled to escape marauders and such. The Mormons were also violently driven out of Pittsburgh.
Mormonism was also set up by deviants who wanted to have sex with multiple women and children.
And I’m sure cannibalism is somewhere in there too.
Outside Episode 3 I haven’t seen much to mark it out from all the other apocalypse shows. Endless depression and lack of hope. I have enough of that here.