The probelm is that if you are making a historical film, most people will take it as being fact, as most people will not realise the truth for themselves. For example:

Pearl Harbour
U571
Green Berets

All bad films, imho. THe first two make it look like the USA won WW2 on its own, the last is pure propaganda rubbish.

I hate to break the news to you…but all the war films made by all the countries involved in the war were propaganda! Yes, even the UK.
“Target for Tonight, Spitfire, The Lion has Wings, One of our Planes is Missing” and others from the UK, as well as “I wanted Wings, Flying Fortress, Flying Tigers, Mrs Miniver (the the dozens of other pro-UK films made in the US), Bombardier, Captains of the Clouds” from the US.. are now seen through modern eyes as propaganda.
Even postwar films…the beloved Dambusters overestimated the damage done to German industry and never showed innocents getting killed… aren’t immune to the label. The movie was designed to show the bravery of the Bomber Command crews. The English loved it. I’m sure Germans who survived the floods but lost loved ones in them weren’t amused.

In a similar vein…I hope modern audiences don’t see “Dr. Stangelove” as a fact based look at US foreign policy or an accurate look at SAC.
(Here’s another hint…James Bond is not representive of all UK civil servents),

Only idiots expect films to be history lessons. Even modern news programs and “documentraries” are only as fair/honest/accurate as the person making them… The trouble is there are too many idiots out there that believe whatever they see on the screen or TV.

Pearl Harbor wasn’t accurate, neither was Breaking the Sound Barrier.
I’m sure there were/are UK films that gave people the idea that the UK singlehandedly won the war. I’m sure there were German films in production telling their population THEY were winning the war…even as the Russians were storming Berlin.

Here’s a hint…when you go to the cinema, don’t go because you want to learn something. Go because you like the star or special effects.