It's a sad fact of the world: some people just do not understand the appeal of fishing or hunting, and feel so strongly that they have to do something about it.
It's always an unfortunate experience to be out on the lake and have something ruin it. Whether it be a broken rod or a lost lure, few things can ruin a day. However, when people start harassing you, it can be a total mood-killer.
The man in this video states in the description that he constantly has issues with these two people in particular. In the video, they let their dog out into the pond/lake for some swimming time, right when they see the kayak fisherman. He also says that the body of water is disgusting, with broken glass and the like in it, and that it was incredibly dangerous to let their dog into the water just to bother him.
As he says in the video, he knows exactly who these people are and that they consistently try to deter him from fishing this particular section, even though he has made sure it is perfectly legal for him to fish there.
You have to wonder why some people mess with fishermen, of all outdoor sports. Typically, anglers keep to themselves and when you're a kayak fisherman, you make even less trouble because the craft is so small.
Remember, if you're ever harassed in the great outdoors and you know for certain you are legally allowed to be there, stay cool, calm, and collected.