That fact why those fishermen thought they were in the right to stab him doesn’t matter in a short abbreviation that I posted.
Those fishermen (now convicted criminals) were in the wrong all the way.
According to this article, the beach at Jialeshui is divided up into a surfing area and a fishing area and these fishermen had set up their lines in the surfing area. Moreover, you can’t fish at all at this beach from March to May.