Less obscene?

I was surprised for an R-rated film set in the '70s had less obscenities being spoken out loud in enough curse words. There's only four f bombs and not one of them has a sexual connotation, which makes it surprising how we don't hear *beep* being dropped at any reference to Ben and Janey's affair especially after Elena learns about it. Either the characters are too classy for middle aged bourgeois suburbanites to speak that vulgarly or Ang Lee doesn't have as profane of a voice for dialogue as Quentin Tarantino, Martin Scorsese, or Paul Thomas Anderson do for most of their films. Most of the cursing is just standard dialogue that you'd hear in a PG-13 action movie and there's hardly any slangs about sex than just using the word sex. Not that making it sound more obscene would made it a better movie but it would have just made better sense for a film about the '70s when most films on that era, at least of the R rating, let a lot out.