MIAMI — While voters all over Miami-Dade County were casting their ballots in the contentious presidential election on Nov. 3, 2020, police say one Donald Trump supporter was dangerously expressing his political opinions out on Biscayne Bay with threats and a handgun. Triggered, police say, by a Joe Biden flag on a personal watercraft, Eduardo Acosta allegedly went ballistic and attacked two men, firing at them as they fled on the water and then chasing them down and threatening them at gunpoint — all while repeating a conspiracy that Biden supporters are child molesters. Two years later, Acos…