"In his book, Body of Secrets, James Bamford, who spent three years in the United States Navy as an intelligence analyst, writes, that the primary purpose of the Maddox "was to act as a seagoing provocateur—to poke its sharp gray bow and the American flag as close to the belly of North Vietnam as possible, in effect shoving its five-inch cannons up the nose of the communist navy. ... The Maddox' mission was made even more provocative by being timed to coincide with commando raids, creating the impression that the Maddox was directing those missions ..." Thus, the North Vietnamese had every reason to believe that Maddox was involved in these actions."
The US was already neck deep in Vietnam, what they needed was an excuse for going all in. So they started poking the bear, which is exactly what they're doing right now with Russia, Iran, China and probably more.
Wars are not started by coincidence, they are very well planned and always come with a hidden agenda.