FORT LAUDERDALE, Fla. (AP) — A 23-year-old man who posted on Facebook, “I don’t know why I don’t go on a killing spree.” A West Palm Beach couple who shot up their home while high on cocaine. A 31-year-old Gulf Coast man who pointed a semiautomatic rifle at a motorcyclist. All four Florida residents had their guns taken away by judges under a “red flag” law the state passed three weeks after…