I understand guys head to the track to enjoy the comradely and blow off steam. I also don't think it's a big deal if someone occasionally lets something slip out of their mouth that isn't good manners....but it's usually a big mouth that continues to drop the F bomb or feels the need to share his inappropriate story with the entire track instead of just his couple buddies that makes it not kid friendly. I'm not having a conversation with my kids explaining why it's ok for people to talk like that...that's not being a responsible parent?! Why would I need to justify someone else's behavior to my kids or I'm not being responsible?
I think when in public with the possibility of younger folks being around you should be a responsible adult and keep your swearing to a minimum or at least keep your voice down....that's basic manners. Go to a bar or any other number of places that don't have kids around to let it fly. Contrary to some peoples opinion, an RC track/racing IS a family friendly activity.
It's not at a first amendment issue... It's a lack of common sense and manners issue.