He didn't say they were cursing, but saying things that they were not supposed to say.
Well, we did it on VMK. We "dictionary danced" to say what we wanted...even the mods....we used the excuse of being adults and needing to say 'certain' words to get a point across or explain something better. (I'm not talking about bad words, just words in general...)
They, the children, learn by example, not by what we say to do. If we pick and chose which rules to obey and disobey it shows that rules are a 'gray' area. We can obey or disobey according to our own judgment and circumstances.
Whether it be in life or virtual, same thing... It is difficult to expect them to be better than the example we ourselves show to the world.