@RidgeTop. Good quote. He certainly lived up to his words when he made Avatar. I know a few right-wing conservative types who find the film unwatchable because of its "lefty liberal" themes. (Their words not mine, but probably not inaccurate). I can watch it just fine.
@SiL. No, it's not a horrifying new development. Yes, it's par for the course. What is new is the new slang terminology being used: "Woke", "SJW", "diversity" (we used to use the word "inclusivity") making certain people think there's a new leftist conspiracy afoot. There's not. Basically, storytellers have been putting messages into their stories for as long as they've been at work. (e.g. The Bible).
Messages, or themes, are generally layered as subplots within the overarching narrative. IOW, it's normal for a film (or novel, or play) to be about more than one thing. Generally, you've got your main plot on top carrying the action (the actual step by step events that comprise the narrative), and layers of subplot underneath that carry the theme.
For example, in Aliens you've got the top level of story: A woman teams up with some soldiers to defeat an alien threat. That's the action layer—the main plot. Layered below that are themes of corporate malfeasance, redemption, the hubris of technology, the brotherhood of soldiering, the eminence of the innocent (Newt and Bishop, one who is a child, the other who is child-like). These are the subplots that carry the themes. All these ideas co-exist in the Aliens screenplay, in varying degrees of emphasis.
At the very minimum, any audience should be able to follow the action of the main plot. If you're a 9 year old kid, or a shallow viewer, or simply inattentive, the action level will at least entertain you. But in any good film, if you are inclined to look deeper, the themes will be there.
This is also why Hill and Giler were so derisive of the original Alien screenplay that O'Bannon wrote. Basically, there were no deeper layers to the story. That's the hallmark of a B-movie. Whatever the events are in such a story, that's what the story is about. It's all surface level. It's why they added the subplot about the Company. It's why Mother was intended to be a corporate agent, plotting against the crew (later rewritten as Ash). This added what they felt every respectable script needs—a subplot to carry the story's theme. Without this subplot (and the friction between the lowly engineers and the upper-deck officers), Alien had no theme. Hill and Giler put one in. (Naturally, being the mid-70s, post-Watergate and the Nixon-era, with films like The Parallax View, Three Days of the Condor, The Conversation, The China Syndrome, The Candidate, etc. the zeitgeist of the era spawned many political thrillers about villainous institutions of authority; unsurprisingly, Hill and Giler shared the same influences.)
(Before anyone objects to say that O'Bannon's script had a built-in theme of rape, let me say at this point that rape is not a theme; it's an image-system. Likewise, neither is "motherhood" a theme in Aliens; technically, this, too, is an image-system.)
The interesting thing is that with the simple addition of this theme-bearing subplot (the Company, deviously plotting against its own workers) they created the germ of a franchise-wide theme that all sequels, and the vast majority of EU material, used as a toe-hold in developing their own descendant stories. IOW the importance of that theme can't be overstated. Without it, the entire Alien franchise might have had nothing more to show us than repetitious Giger-monster rehashes.
TC