That doesn't make it okay. Humanity has a long history of a lot of bad things. Another one is even featured prominently in this manga.
Anyway, your premise is wrong too: most of humanity didn't have tobacco until a couple centuries ago. Tobacco was a New World plant, like coca.
The Potato is a New World plant also but I bet you wouldn't complain about Granny and Elf enjoying some taters, this is a stupid argument. If every fantasy setting were historically accurate to the setting that inspired them, for example, medieval/early Renaissance Europe, then it would be more accurate for The Lord of the Rings to have Samwise Gamgee sing a song about how much he loves going out hunting with his hand cannon, than singing about the many ways you can cook a potato. Because Europeans have had access to firearms longer than they've had access to potatoes, cause they are native to the andies of South America.
I bring up the medieval/early Renaissance because these periods do overlap. The Medieval period is generally accepted to have lasted from the late 400s to 1450 - 1500 at the latest, and the early Renaissance is accepted to have started around the 1400s.
As you can see from the long period it lasted, using Medieval as a specifier for a genre, is kind of an ass and a half, Westerners such as us tend to quantify the Medieval with the earlier periods of it (Game of Thrones, LOTR, Asterix & Obelix), whereas Easterners will tend to quantify it with it's later periods, (Ghibli Movies, This Manga).
This brings us back to the potato and historical accuracy, the first European to have consumed it would have more likely been a gun-toting conquistador from the 1530s