Even if they're put out of a career, they'll still be receiving container royalty payments until retirement (even if they get another job). More expensive ship

Even if they're put out of a career, they'll still be receiving container royalty payments until retirement (even if they get another job). More expensive shipping is a regressive tax: any product requiring shipping becomes more expensive. Dock workers are quite literally demanding worsening income inequality: they make well above average wages, and the cost of their demands would be borne by the public at large who on average make less than dock workers.