Well, I know kids today aren’t being raised with the same protections I was as a kid. Kids swear more often now, see more violent tv than I did, and see sex more often than I did.
Unless you're like 80, that's not true at all. Every generation since gen x has gotten more prudish.
"And behold, I Myself am bringing floodwaters on the earth, to destroy from under heaven all flesh in which is the breath of life; everything that is on the earth shall die." - Genesis 6:7
"If you had not committed great sins, God would not have sent a punishment like me upon you." - Genghis Khan
I've got a similar story that I've been workshopping for years...the alien races decide humans are too warlike, and after our first space war (against other humans, with us not knowing aliens exist yet) the alien council ruling the galaxy decides we're too dangerous and getting too technologically advanced, so they send an AI to try to wipe us out. Galactic civilization has been largely peaceful for tens of thousands of years so they don't know how to do war, but they program an ai to try to eliminate humanity while preserving the rest of life on Earth.
They mostly succeed, but in the conflict the earth does get devastated despite the best efforts of the AI. A human colony ship escapes, and hundreds of years later the descendants of the massacre return to wreak bloody vengeance on the rest of the galaxy.
Eh. The amount of oxygen in out atmosphere is pretty much impossible by non-living processes alone iirc. Anyone who can do astro-spectroscopy can probably tell there's life here, from thousands of light years away.