Kitties are just like that, fascinated with paper, with the scents they hold, the noise they make and how fun they are to shred.
You can distract your cats easily enough with a diversion of paper. Take one of those old telephone books you might have stored in your home. Here in our area, we must get a new one every few months
Take the old phone book, put it on the ground and sprinkle some catnip into some of the pages, then just open it up and let your cats have at it. It does make a mess, but it saves mail, toilet paper, paper towels and other paper items from being attacked.
All cats shred paper, no one really knows why though. I did an article about it a long time ago, if you are interested in reading it just drop me a note and I will send it along.
Don't get mad at your cats, they are really just playing and having fun-