Invasion of the Body Snatchers had a political message in it? I haven't seen the newer version, but I've seen the original several times, and I don't recall any. I thought they were just the victims of an alien invasion.
[Currently, I'm trying to follow "The Event," which had somewhat of a political message to it last season, but there's been a plot twist this year, so I don't think it's going there. Looks like those "aliens" might not be aliens at all, but the people who once inhabited earth and were shipped to outer space for some reason years ago.]
I love science fiction, if it has a credible plot, and I'm not usually looking for a political message in any of it.
Invasion of the Body snatchers (both versions) can be construed as a political metaphor.
The original could be construed as a commentary on US fears that crypto-communists were taking over society.
The 1970's version I personally construed as a metaphor about YUPPIES taking over society. (and it all came true, too, much to this nation's shame)
I've actually seen that picture at least ten times, since, in the late 70s I used to drink in a bar that showed it a couple times a day for about a week.
Insinuating social commentary metphors is rather common in literature and film.
For example,
Animal Farm isn't entirely just about farm animals.