The union might have a case if the protest were related to work rules, safety violations, pay negotiations, and other things that unions hold out to their members as justification for paying dues. This protest is radically different from the norm. It's about a court decision that prevented a one-day union walkout at Bay Area ports to express solidarity with greedy public sector employees in Wisconsin.
Port union leaders have lost their minds. They are blind to the frustration taxpaying Americans feel with public employee unions that demand endless pay and benefits for less performance. Behavior like this by port workers makes America less competitive. China and India are laughing at America for tolerating union stunts like this one.