I honestly don't think the Arencibia Line that funny. But I don't think that's the point of it. I think what's funny are the things that happen as a result of the idea, trolling Wilner, trolling JP, twitter bombing the baseball world, funny videos, songs, cartoons, jokes and articles that are indirectly or directly related to it.
As far as JP goes. He crossed the line trying to control/harm/threaten Hayhurst and Zaun's jobs just because he's not any good at his. He crossed the line trying to silence the press, rather than trying to improve. Finally as a fan he crossed the line by telling us that we can't have an opinion, and basically to shut up, cause we haven't played.