system
Given the following post, respond as if you're commenting on Reddit:
human
[Alien] How come humans didn't have contact with Alien life before the first movie?

The way the first movies go, we're lead to think it's the first time humanity is dealing with alien life, but in a Universe where the Yautja  hunt Aliens for sport, enough to rank some as worthy and unworthy kills, we're lead to think that the Universe isn't as empty as we first thought, are humans just bad at finding life? Or do we just chuck it off to bad luck?

UPDATE: It was pointed that in Aliens one of the marines talks about fucking and alien, but then, in the same movie, one of them says something around the lines of "She's (Ripley) supposed to be some kind of a consultant, apparently she saw an alien once." as if it's something looney, which strikes me as odd.
gpt
It's more accurately like finding a needle in a haystack built out of needle like hay from a mile away with a jeweler's eye piece.  Human exploration is in it's infancy still and requires a massive investment of resources and time to discover and visit new worlds and stars.  It's profit vs cost really.  Why throw trillions into finding potentially habitable worlds and life when you can exploit resources on dead planets and see a return on investment sooner.  It's implied the predator and engineer ships travel much faster than any human vessel and have near limitless energy to do so.  A predator clan can find a new hunting ground in a few months a human colony ship will take potentially decades to do the same feat.