WHat I would say is that all drugs can have both good and bad effects…. and these all need to be weighed up. Yes, cigarettes cause cancer, but weed also has plenty of negative effects! It can permanently alter your brain chemistry in ways we don’t fully understand yet. For example, it has been linked with lower intelligence and a worse memory later in life. It’s purely down to each government where they draw the line with regards to wat they think is safe and what’s not. Alcohol for example is banned in some ‘dry counties’ in the USA! (the jack daniels distillery is in one!). A lot of hard drugs are illegal everywhere because of the severely harmful effects that they have on people, and they also impair their judgement in the short term, making them a danger to themselves and others around them. Cigarettes are legal I guess because although they cause cancer, they don’t have much effect on people when they smoke them, so the government don’t care as much. Plus you also have to take into account that so many people smoke that trying to ban it would be hugely unpopular! And the sales of tobacco raises a lot of money for the goverment in taxes too… The same argument can be made for alcohol.
Cigarettes do cause cancer and other diseases, but smoking cannabis is far from safe. Cannabis causes changes in brain chemistry and can leave smokers at a higher risk of developing mental health issues.
Marijuana is actually legalised in some areas of the world, like Holland including certain states in America, where they allow it to be smoked for therapeutic reasons.
I think the reason that some drugs (like alcohol and cigarettes) are legal, even though they cause high rates of addiction and cause disease but others are illegal is probably down to our historical use of them. In England people have been smoking cigarettes and drinking alcohol for a long time so it has become culturally acceptable, whereas smoking cannabis is frowned upon by most of society.