Christians don’t usually object to subject matter. The depiction of it is another matter. I can contemplate Christ being tempted to come down off the cross to live a “normal life”, but I don’t need to see him having intercourse with Mary Magdalene visually depicted to get the point. I get that The Bad Lieutenant was “Bad” but I don’t need to see him masturbating in front of a couple of girls to get the point. Such graphic depictions are actually infantilizing and condescending to the audience. It screams — “This guy is a pervert and since you are too stupid and I’m too lazy to show that artfully I’m going to show him actually masturbating in front of the girls. Get it? Get it?” It was shocking in Midnight Cowboy perhaps in 1968. It’s disgusting to see in any case and there are myriad other ways to get the point across.I debate internally a lot about the boundaries of art and showing graphically problems like human trafficking and the sex slave trade, drug addiction, etc. That using irredeemable methods to redeem the world would be off limits seems to me to be a given. Pornography is obviously off limits and asking real people to get naked and get in sexual positions simulating sexual behavior would seem off limits. Language? Violence? You can't make a decent war movie with "shucks" and "darns" and part of the impact of Saving Private Ryan and Spielberg's tour de force D-Day landing opening was its graphic brutality highlighting war's gruesomeness. The debate as to the limits, utility, and righteousness of theme, method, narrative, etc. in art goes on and on.
I agree — the theme of The Bad Lieutenant is very redemptive and Christian, but in a Monty Python and The Meaning of Life sort of way where John Cleese’s teacher actually has sex with his wife in front of the students for sex education. The message of The Bad Lieutenant is redemptive (for those who are attuned to it), the depiction is carnal (where everyone is attuned to that) and overwhelms the message.
We are in the world not of the world.