The cyanide thing was a single person covering the murder of their spouse by contaminating a bunch of Tylenol at the same drug store. And that happened decades ago. It’s why there are so many “tamper evident” seals now.
Unless this actually happened recently and I just never heard about it.
Funny, I have the opposite complaint about Fallout 4. In what is supposed to be a nuclear wasteland of a city where everyone is struggling to keep their small communities going, there are just too many people in such a small space to make this feel real. I liked Fallout 3 and New Vegas more because the world was properly empty, but still had so many things to discover.