why rated R?

I also seem to recall the breaking point for the marriage early on is when Susan Anspach discovers husband George Segal in bed with his black secretary, who is topless. My memory might be a little foggy, but I remember this moment cuz it's what caused my offended parent (nudity! and a Negro woman! what filth now passes as entertainment! or such were his general sentiments) to yank me out of the theatre at age 13.