True but all they needed was one line to explain that it was modified. It kind of annoyed me as well because at face value it doesn't make a lot of sense.
"By law you have to call it a lair if you use it to torture people." Douglas Davenport

Cadmus modified it so that it wouldn't kill Humans.
Later on Eliza was so skilled at modifying it herself that she could use it to kill White Martian cells while not doing anything to Green Martian cells.
By this logic Cadmus could also modify it so it would kill Kryptonians.
But, Cadmus wanted to deploy the virus so they could see whether or not it would work. Releasing it in the alien bar was an excellent test, because a number of different alien races were represented in there. In addition there were humans, 0% of which were people Cadmus cared about. So, if the virus also killed humans, no big loss to them. In fact, Cadmus probably writes the humans who work in the bar off as alien sympathizers.
I would assume that Cadmus, once they discover their version of Medusa was a success, could then modify it to kill Kryptonians too. Who knows, perhaps the version Lillian Luthor thought she was releasing over the city was going to kill Kryptonians also but was instead foiled by her daughter's shenanigans.

You're forgetting Zor-El designed it to kill all aliens who were not Kryptonian.
Granted they studied Earth/humans and might have had access to human DNA.
So what are the chances that humans would invade or attack Krypton?
With less than a snowball's chance in hell of human attacking/invading Krypton, there would be no need to modify the virus to spare humans. They could go back and modify it later when the Earth starts visiting other systems. But that would be tabled for another date.

You're forgetting that Kryptonians have studied Earth for a long enough time to determine whether or not an invasion force from Earth was a threat.
That's one of the big things in the comics, that Jor-El knew about humans, and wanted to let his son live with them.
He knew what powers he would gain.
Zor-El knew the same, because Zor-El isn't stupid.
So, yeah, this actually has a lore reason for not effecting the humans.
I am a man with Asperger's Syndrome, so please forgive me if my posting seems weird.

To the OP, I was wondering the same thing. I figured that the writers were lazy. Human's are aliens to Kryptonians, so the humans would have been dead along with the other non-human patrons at the bar. I hate when writers get sloppy, the exact reason I stopped watching Zoo. They kept says that a mutation was effecting animals, meanwhile, humans are animals (Great apes).

To Film Extra: I agree. Cadmus knows that at least two of the most well known protectors of Earth are Kryptonians, so wouldn't they would want to change it to get rid of them first, if they changed it (not due to sloppy writing where they think people watching the show are all stupid).

Well if your going on the assumption that they modified it to protect earth humans wouldn't you also assume the modify it to kill Kryptons too?

Well I assumed they changed it because what would be the point ifit was gonna kill all of Cadmus. It's not like they aren't capable of it. I thought this was obvious

arguably you could say they re-calibrated the baseline so that it recognizes what belongs in the Biome in which it is deployed and that it was the Red Sun Powers that allowed Kara and Mon-El but my guess is the writers weren't that invested they made ups something that sounded science-y and ran with it