Most movies require a detailed understanding of the culture in which those movies originated; Audiences without that understanding simply won't get a large part of what they are seeing.
The whole first half of the original Terminator movie is meaningless in a world where everyone is carrying a smartphone, for example. Sarah Connor has to find payphones (and coins to use them) or plead with businesses to let her use their phone; It's a central part of the way the movie builds tension as the T-100 inexorably closes in.
Now try to imagine just how much of that movie would be inexplicable to a person who has never seen a telephone of any kind. Or a radio. Or a motor vehicle. Or a computer. Or an automatic weapon.
And that's just the stuff. The geopolitical background is needed too - without an understanding of the Cold War; of the existence of opposing world destroying nuclear arsenals, and of computers that could launch those arsenals; Of a war that could kill everyone and destroy everything in a few hours; Of why it is felt to be useful to have such an arsenal, and to place it on a hair-trigger; Of what the Soviet Union is, where it came from, and why it is The Enemy; Of the rapidly growing technology that made the 1980s a terrifying and out-of-control example of hyper-modernity in which people were left floundering at the mercy of events they had no ability to influence, much less to control...
You would need to spend a decade teaching the Founding Fathers a couple of centuries of history and technological advancements, before they could even grasp what they were looking at; And they would likely never really understand the movie, unless they had lived through the 1970s and '80s in real time. In the same way that someone born too recently to remember the Cold War likely will never really understand Terminator, no matter how much they might enjoy the action.
Don't even get started on movies which have deep plots that are not just a vehicle for whizz-bang* special effects, explosions, and car chases.
By the age of nine, a modern person has been exposed to millions of "tropes". That exposure is a prerequisite for understanding most movies. And it is practically irreplacable - like learning your native language. Teaching an adult to become completely, natively, fluent in a foreign language is very hard indeed. Teaching George Washington to grok modern movie tropes, to the point where he could comprehend even half of what he sees in any movie, would take years of hard work.
Showing him any twentieth century movie would be like showing him a movie in Mandarin without subtitles. He might grasp the broad themes, but much of the detail would just be confusing and incomprehensible.
* The very phrase "whizz-bang" didn't exist at all until the late 19th century, when it was coined to describe the sound made by the German 77mm FK 96 gun, introduced in 1896. It fired a very high velocity shell, so rather than hearing the 'bang' of the gun firing, followed by the 'whizz' as it flew past, its targets heard the shell first, then the gun. Use of the phrase to mean 'very advanced technology' became widespread in the Great War, where that gun was particularly devastating, and widely feared by the British front-line troops.