It's the sort of social satire that hasn't aged that well but by most accounts was more effective at the time. Kind of set the stage for things like Taxi Driver.
A hell of a lot better than The Magic Christian anyhow, from what I remember. The album "Joe Speaks" that was released as a tie-in is pretty special, too.
Kinda reminds me of a bizarro God Bless America starring Young Frankenstein instead of Bill Murray's brother. That movie had a lot of flaws but the Westboro scene sure was fun. I guess there's two ways to see this movie and it depends on which way you interpret Merle Haggard's Okie from Muskogee or Skynrd's Sweet Home Alabama. I dunno I might check it out but the trailer kinda gives it away.