In other words: People who happen to drink coffee, for some reason that may or may not be related to coffee, live longer on average than people who don't drink

In other words: People who happen to drink coffee, for some reason that may or may not be related to coffee, live longer on average than people who don't drink coffee. Do people who don't drink coffee have lifestyles similar to those who do? On average, I highly doubt it. Observational studies are terrible when they generate headlines, but good when they generate controlled, scientific studies with proper isolation of variables. Since this is super expensive to do with humans as test subjects, it's not done very often, leading to piles upon piles of shitty science pertaining to human nutrition.