It's all about profit for the government, my dear. Whether it causes death or health problems for somebody is irrelevant. The government is full of heartless shitbags who simply do not care.
But just because alcohol or certain drugs may cause problems for one person should not matter to you. Take people who use meth or heroine for example. They are KNOWINGLY causing serious damage to their bodies and lives, and yet they still continue to do it. It is in their own self interest to harm themselves. It's their own lives, and their own bodies, so why should you care what they do with it? It shouldn't be a problem as long as it isn't harming other innocent people that didn't want anything to do with it.
With this logic, alcohol and liquor is worse than meth, cocaine and heroine. Look at how many people die due to car accidents induced by somebody who was under the influence. They weren't the ones who were drunk, but they still ended up dying for something that wasn't their fault. Some people get violent and end up beating up or killing other people when they're drunk. Not once have I ever heard of somebody doing this to another person when they were taking drugs.
Which brings me to my next point. All drugs should be legalized, regardless of how harmful they are to the person taking them. Their body, their choices. Let's use gangs, and the drug war for example. When alcohol was illegal in the United States, gang activity was fairly common. Not surprisingly, said gang activity decreased after the use of alcohol became legal again. What makes you think the same results wouldn't occur if we were to legalize drugs? When certain items are illegal, they begin getting traded under the black market, which makes said merchandise more expensive. When people become addicted to things like drugs, they are so desperate to get ahold of it, they will do whatever they can to get the money to afford it. This usually results in more robberies. Keeping drugs illegal harms other people more than it does when it is legal.