If this were a passage in a reading comprehension exam, I think you would be expected to read "cocaïne didn't exist" as "cocaïne in the form we think of when someone 'does cocaine' didn't exist".

You would be expected to read it this way because the article explicitly elaborates on how cocaine hydrochloride is isolated from leaves (that alone should have stopped you from trying to "inform" anyone), and uses that to drive the main thesis about the industrialization and democratization of drugs.

And that's an entirely self-contained pathway to the correct reading, nevermind what you already knew going into the exercise.

The caffeine analogy is useless because there is no common sense of people using caffeine to very different effect the way there is for cocaïne.