The enemy is not 'us'

There is in fact no evidence humans created the bio agent, and it was presented as probably impossible for that to be the case. The cynical man who doubted everything everyone else said made his last cynical remark claiming the probe could have picked up the bio weapon in space and infected the aliens who then retaliated. In fact, every other statement he made in the film was wrong, why would you believe this one, based on no logic or evidence?

This is an irrational and unlikely scenario. First of all, space doesn't create bio weapons. So someone made it in the first place, so it was either humans or aliens. Humans weren't aware of aliens to begin with, so there is no rational reason for them to make it, and it is simply insane to think humans made a bio-weapon that affects humans to use on aliens they don't know exist. Nor is it rational to think that an Earth probe within our own solar system just happened to pick up something deadly that these aliens found, which had to have then be created by a third alien race that placed it on an Earth probe to kill the second race, because that's literally the only possibility for this unreliable character's guess to be true. And even if that were the case, why would an alien race picking up human technology in the human's solar system get so personally offended by it that they would create a bio weapon that could wipe out the species? That is f-ing ridiculous. The only logical answer is it was maliciously designed and placed to kill humans by a malicious alien species.

The technology used to disperse the bio weapon that affected humans was alien. So it is a fact as presented in the film that aliens took a harmless space probe and loaded it with a bio weapon that affects humans. Then tossed it back into space for humans to find and die.

The synopsis for this film written by Skewter is entirely inaccurate. Faced with a bio weapon and an unlikely chance of anyone's survival, it was good-hearted humans with quick wit and skill who managed to save most of the crew, and it was honor and love that allowed the two humans to die rather than infect more people. This film presents good people making good decisions and overcoming great challenges. The enemy is the alien race who planted this, possibly to stop human expansion into the galaxy.