system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If cigarettes are poisonous and addictive, why are they not illegal?
gpt
This post is young, so maybe this won't get buried, but hopefully you'll see it.  

It's because for a stretch of time going back to when this country was founded, tobacco was one of our biggest cash crops.  It was so profitable, in fact, that it worried a lot of farmers because they were worried about not growing enough food to feed the country.  It's still a vital part of our economy.  

Now unbeknownst to a lot of people, tobacco was something that was discovered in the New World when North America was settled - and quickly spread in popularity throughout Europe.  It was seen as one of the riches of the New World, a portent of an exciting age of discovery, something exotic from a land far away that no one had seen before.  

Keeping this in mind, that tobacco saturated our culture and usage carried on for nearly 500 years without any concern for ill effects on human health, and only in the last 50 did we even realize the harm it was doing us, that the historical and economic momentum can't be stopped overnight.  

Edit: grammar and spelling.