system
A chat on subreddit /r/PoliticalCompassMemes
human
"The British" didn't kill a bunch of them. It was one weird pervert who seemed to have a fetish for them. He abducted a few of them, two died, the rest were sent back.

He had his crew take him to the island and once there he captured a few kids and an elderly couple. He brought them on his ship to meassure their genitals, do some phrenology, and all kinds of other "science" experiments. He also took a lot of weird naked photographs of them posing as Greek gods or some shit. Then the elderly couple got sick and died so he took the kids back to the island with a bunch of gifts as an "I'm sorry for murdering your elders" present. 

But you're right about that most likely being the reason they kill outsiders on sight. 1st contact was not pleasant for them.
gpt
Thank you, I had trouble remembering the details of the encounter, and they are truly bizarre and deserve the justice you gave them.

But yes, if aliens showed up, abducted a few people, molested some kids, then said "oops, sorry we killed the adults, anyway here's your traumatized kids back with some space knick-knacks" We would probably not tolerate any extraterrestrial visitors anymore.