I quite agree. I occasionally buy a DVD I like the look of - but if there are four-letter words it goes straight in the bin! One example is a film called 'Goodfellas' which I bought recently. The first few lines were "What the f--k". "What the f--k was that?" "What's that f--kin' noise?" etc. That went in the bin within a minute!
With regards to swearing being 'realistic'. I know plenty of people who refer to blacks, homosexuals etc by various terms we all know. That's what happens in the real world so it's realistic, yet TV wouldn't transmit those words now - as they would say they are offensive! It's very curious how swearing isn't considered offensive, yet words we used openly a generation ago now are.
Secondly, being 'realistic' isn't necessary anyway. Films aren't documentaries. It's only today's trashy rubbish and trashy actors and actresses who need to swear. The best films, despite their subject, have no swearing in them (Bonnie and Clyde, Dillinger etc). I never heard John Wayne swear - he was too good.