The "immediate threat to human life" was not identified specifically; the only post meeting that description was taken down by moderators in less than an hour (which compares favourably with many social media sites' response times to similar incidents) and was from a new account that hadn't posted anything else, so hardly representative of the site's culture.
While I don't know the specifics behind your other link, like most articles about it it's using second- and third-hand claims; given there was an orchestrated smear campaign against the site, I'm sceptical. It was certainly convenient that Kiwi Farms was removed from the Internet Archive just as articles like this were being published, making it impossible to verify or disprove any of their allegations. If you're worrying about sources (which you are absolutely right to!), I'd start there; do the posts that article is talking about actually exist?
https://fortune.com/2022/09/05/kiwi-farms-so-bad-cloudflare-...
It is anything but false. They bragged about their kill count. Do you have any source for your claim?