Retired FDNY Lt. John McLaughlin probably should be paying taxpayers for his remarkable fitness as a top long-distance runner, given his years of strenuous work as a firefighter. Instead, as The Post's Carl Campanile reported yesterday, the 55-year-old "Iron Man" triathlete is collecting an $86,000 disability pension from taxpayers. No wonder New Yorkers are increasingly fed up with public employees, as a fascinating poll last week found. Since retiring in 2001, McLaughlin has run numerous marathons and other races, often finishing near the top -- and first or second in his age group. He's "an incredibly fast runner," a fellow...