Five Long Island Railroad unions are threatening to strike in May. Christopher Sadowski Five privileged LIRR unions are aiming to hold the metro region hostage : If the MTA refuses to pay the ransom — a steep wage hike — they’ll strike, possibly as soon as May 16. That’ll shut down the rail line, and much of New York with it. Gov. Kathy Hochul, and her Republican rival for governor, Bruce Blakeman , both need to make clear they’ll stand up to these thugs and prevent them from extorting New Yorkers. “We’re talking about a complete and total shutdown,” the Brotherhood of Locomotive Engineers and Trainmen’s Kevin Sexton threatened this month. “The clock is ticking.” The International Brotherhood of Electrical Workers’s Jeff Klein warned not to underestimate the unions’ resolve: “Our memberships are prepared to do what’s necessary,” even if it means a long, crippling strike. Who do these people think they are? Who do think they’re threatening?…