Stories, plays, etc, have been used to cloak political comments for a very long time. Messages were masked in metaphors if the people expressing them were fearful of consequences; in other cases, they were more obvious. I am not expert on this, but even
Gulliver's Travels was highly political by its metaphors that were meaningful to the readers at that time. The Gospels also employ metaphor in the parables attributed to Jesus.
As far as modern films are concerned, I either like or dislike them for reasons other than such political messages. I thought the Robocop trilogy was full of anti-bussiness or perhaps I should call them "trust the (big & getting bigger) government & distrust private industry" messages. While I disagreed with that, I still refused to let that ruin my enjoyment of the film.
However, I recognise that these subtle messages are at least as effective if not more so, than outright rhetoric. This is because the listener will be on the defensive if he hears statements that directly counter what he believes. Yet, if that rhetoric is hidden in a story, he will likely be less defensive. If he has been reading a story and has come to identiy with a character, that character can in latter parts of the story, express views with which the reader disagrees even strongly, and that reader just might begin to see the other side's view on that issue. I have studied psychology in college, & now wonder if there is a class about the psychology of propaganda. I would enroll if I could find such a thing.
Several factors are at work, though:
1. Group dynamics/peer pressure.
If more than 1 person holds a particular view, that group holding the view has a greater influence than an individual. There were more than a few psychologists who recognised that the mob mentality robbed people of their common sense or ethics. This was true of the Nazi war crimes trials as well as rioting, etc. Experts in psyc argued that had the circumstances been different, it would be appropriate to hold the henchmen accountable, but since they were carried away with a group that collectively did such & such, the personal responsibility could not be proven.
Sorry I am a bit vague on that, but it has been a year since I finished school. If anybody wants clarification, please ask, & I will refer to my text books.
2. As noted above, the power that empathy for the story's protagonist has over the reader's values.
3. as noted above, the disconnection between the situation in the story and that of the real world, allows the writers to express views that otherwise would draw criticism.

Ok, I realize that some have detected political messages in III, but nevertheless, others might not. Of those who do see political views in the films, how many leave the theatre mid film rather than tolerate the film to its end? They may not have agreed with the statement, but they did receive it.
I am too tired to continue this right now. B)
However, I welcome any civilized discussion of my statement.