Cohoho,
Sounds like you ran into one of the town idiots. There's a more than a few, even in this small town. Let me start by saying that it sounds to me like you guys did absolutely nothing wrong, but let me tell you what we get to deal with on a daily basis in the summer. I used to rent the upstairs in that duplex right next to the fish factory, right near the boat launch. Multiple times every day people would pull their boats into my driveway, grab my hose off the side of my house and start washing their boats off, fillet their fish right in my driveway, then throw the carcasses in my garbage can! WTF?? I ended up having to store my hose in my hose, padlock the water spigot and hide my garbage can. My neighbor that was next door (it's a vacation home) said when he got there for a weekend he had to pick up about 45 sturgeon carcasses out of his yard. Again not defending the guy that went off on you, or saying that you guys did ANYTHING wrong, just letting you know some of the things I dealt with when I lived next to the boat launch.
