I think this is almost like asking whether jumping into shark-infested waters is more dangerous than jumping into a fire. Using drugs in any form is dangerous; they simply present different types of danger.
While it is true that tobacco, alcohol, and marijuana are more readily available drugs, that doesn't make them less dangerous. Around 1,300 people die each day from smoking, and the health impacts cause other secondary health issues as well. Alcohol is the third leading cause of preventable death in the United States, claiming around 100,000 lives annually. And while marijuana is typically hailed as a "safe" drug, there are people whose bodies reject exposure to the drug (as any drug), causing potentially fatal complications. Like alcohol, it contributes to the numbers of those driving under impairment and inflicting harm while behind the wheel of an automobile. There is an epidemic of teenagers flocking to new forms of tobacco use, such as juul pods, and there is also a growing trend of hospitalizations stemming from lung disorders from this trend. Alcohol is linked to everything from domestic violence to liver cirrhosis. They all present innate danger.
Tobacco isn't the only drug with rising trends toward deadly outcomes. While 2003–2013 saw relatively stable cocaine usage, there has been a sudden increase in recent years. In fact, in 2015 alone, deaths attributed to cocaine grew over 50%. Of the 70,000 people who died by overdose in 2017, two-thirds died by opioid use.
People tend to classify cocaine and opioids as more dangerous drugs because potential death happens more quickly. Overdose rates are high and are easily attributed to cause-and-effect relationships. However, drugs such as alcohol, tobacco, and marijuana are powerfully dangerous in their own rights; instead of a quick death, these drugs often have the power to diminish health slowly over time, leading to a slower death.
Ingesting any drug can have life-ending consequences, legal or not. There is always a potential for danger in their usage, which makes it hard to differentiate between degrees of risk.