And that makes sense because the lighter the oil, the more surface area the ball will have in contact with the lane. More oil means less aggressive balls will hydroplane, while the more aggressive balls won't have a lot of surface area in contact with the lane, but they will have some.
Did you read the articles? It's like tires. Racing slicks are perfect for Nascar, because the surface is dry tacky asphalt. Could you use them on snow? Hell no. How about snow tires? Better for snow, but not perfect, but could you use them on a stock car? They technically have more grip, right? Not the case, they'd shred inside of a lap while the car is sliding all over the place. Same deal with "aggressive" balls on dry lanes. They just roll out and die while your tropical heat goes nuts. Same principle.