I think the parents doing the hollering are over-reacting. It's done, it's over. Let it go. It was one word. If these parents don't think their children have never heard it before, they're not doing a very good job of parenting to begin with. They are out of touch.
My kids are 10. I know they hear the 'f' word at least 20 times a day, especially my son, as he hangs around with boys. That's what they do. They play ball. They play in the creek. They cuss.
They don't, however, hear it in this house, from their parents. All you can do is teach your children what you believe to be a decent way to live, and hope they follow your example.
That's not to say I don't agree with Sue, though, because I do. There has to be some sort of limit on what filters through and gets into my living room on the TV.