If a movie is made of factual or historical events which happened within three or four decades, should the movie makers stick as closely to those facts as they can?

I have read several write-ups about American Sniper, all of them stated inaccuracies or pointed out parts of the movie that embellished what really happened. Many of the people involved with that war and with Chris Kyle are still alive. Is there really a need to sex-up the facts? It is not like WWI, WWII, or the Civil War where those who participated or dean or those who are still living may have been involved in a different area, etc. justifying filling in the blanks with stories, events, etc. that did not happen exactly as they did. If people, who were involved around an event 0f historical or factual value, shouldn’t the producers and such stick to the fact known or can be supported?