^ We did not make that translation. Pocketmofo did, and we chose to honour his work by not messing with his translation.
"Fuck" is just a word. It's not really going to hurt anyone. The people that read One Piece online are teens and adults, not children.
Also, please note that Japanese can never be -directly- translated into English. It's a language of interpretation.
Like this for example
"Kisama" is a way of saying "You" in a gloomy way, like "YOU!!! >/"
and is often interpreted as "You bastard!!" to accurately convey that persons emotion and what they mean.
One Piece isn't really a kids manga either. It's a Shounen, targeted at teen boys. Either way, it's the new millinium. Kids start cursing at the age of 10. (It's really hard to find a kid that doesn't cuss nowadays.)
So don't get all bent out of shape over it.