A lot of the knowledge the human race has acquired to date has come about by strange and/or unethical means. More often than not it's probably a good thing that we know it, but it's also a stark reminder that not all discoveries are going to be as cutesy and elementary textbook ready as Isaac Newton getting hit on the head with an apple.
There's no getting away from it: we will always have some kind of lesson behind our hard-earned wisdom, and it isn't always a pleasant one. You know how some people like to say that we should separate the art from the artist? Yeah, it's often best to try and do that with a few of the facts that we learn, too.
This is the takeaway of an AskReddit thread that requested people share their best random facts with potentially shady origins. I guess they could end up being useful.