Lots of other things do even more damage to your liver. Like Tylenol (acetaminophen). That's why you have to drink in moderation, so you can enjoy it for years to come. Also, eat a variety of foods that help your living process. Good fats (fish, nuts), veggies with sulfur in them (leafy greens, garlic, broccoli) etc.

Weed is illegal in the US because Newspaper kingpin William Hearst spent a lot of time demonizing it in all his papers, largely speculated to destroy the hemp industry that competed with his paper/logging industry along with the DuPont family, who had recently created nylon. Since you can't tell the difference between the male and female plants from a distance, they get banned. In the end, the reason is still greed.