First, only a few knew it happened. Unless you are assuming that all the ships crew on each ship were all standing on the topdeck with binoculars just 'watching the show'. I assure you, that is not the case.
Second, this movie, this article are proof that after YEARS OF KEEPING SILENT, some people are now TALKING.
So it isn't ridiculous, is it ?
Everyone of a ship would have known if missiles were fired that night. You don’t have to be on deck to know that. A typical destroyer has a crew of 300+. If there were a flotilla of ships involved in the exercise we’re talking close to a thousand. Word would have spread through out the ships what had happened. Since we the movie has not been released we have no way of knowing who these people are that are talking. We’re they key players? And what exactly they said.