I'm going to fight you on this. I'm going to assume the outer four, Animal Farm, Lord of the Flies and Clockwork Orange (book or film, pick one) don't need defending.
This leaves Soylent Green, Gattaca, Brazil, The Matrix, and Logan's Run.
Soylent Green and Logan's Run aren't particularly well-made films, but their influence both within the SF sphere and in culture at large is way larger than their meagre budgets or box office results would indicate. When they came out, they introduced key pieces into the mix that remain as relevant today as they were in the seventies.
Brazil is an amazing piece of film. A true classic that pops up on "best film" list after 40 years.
GATTACA is the weakest one on this list. There was a brief window were it seemed prescient, but that future quickly receded to give way to the mess we're in now. I can take it or leave it. If this scheme made sense, I could probably find a better replacement.
The Matrix... well, I'll come clean with you: I don't really like the Matrix. If you had been paying attention to SF up until then, the Matrix has zero interesting things to say, paving over its lack of originality with pseudo-philosophical platitudes and action sequences. It wasn't even the best "the world is not real and the protagonist is the chosen one and is going to save us"-film that came out around that time. It was beaten by a year by Dark City.
However, not everyone is a sci-fi snob, and for many people that was their first exposure to a bunch of corner stone concepts. Also, it was pretty cool. So I grudgingly allow it.
You're telling me the intersection of fascist doublethink, media illiteracy, and militant misogyny isn't Lord of the Flies? Or that one of the biggest pieces of mainstream transgender media has little overlap with Handmaid's Tale?
What the human race has done to dogs, now we will do to ourselves, with just as little thought to the repercussions this time around as well. In any case, it will be an interesting affair:-).
I mean, it's happening worldwide. As each next one falls, and worse perhaps joins with the others, it will spread even further. Like a pandemic of an idea. Although perhaps there's hope on the other side, since it seems too late to stop it now but after the afterwards there will be ways to build anew. Anyway the important thing, in my mind at least, is to learn and grow from it all.
Gattaca is a parable about racism, in-groups vs out-groups, and the need to keep the powerful from seeing what you really are inside. We've basically always been there.
That's what you took from it? I took the developing space colonies on Saturn, whatever miracle space engine development they got that allows them to get to Titan in One year, whatever security measures they have that allows them to get into orbit without any kind of spacesuit, the wholesale pervasive electric cars, implied sexual dysmorphism cures, the retro noir aesthetic, the possibility of having kids with the best chances at not having congenital diseases and the main character sheer determination on pursuit of his dreams and his sheer disregard for the security of the people depending on him while suffering from a congenital cardiac issue.