Actually Ink, you are incorrect when you say there are no benefits to alcohol. It is widely recognized that in moderation, certain alcohols actually promotes heart health.
As for your statement that Marijuana poses no health risks, that is 100% false.
Marijuana causes increased heart rates and lower blood psi within minutes of using it. This increases the risk of heart attack.
Marijuana smoke contains three times the amount of tar found in tobacco smoke and 50 percent more carcinogens, it would seem logical to deduce that there is an increased risk of lung cancer for marijuana smokers. Studies proving this have been limited, but should not be discounted as there have been limited sampling sizes owing to the illegal nature of the drug.
Marijuana usage inhibits the ability of the immune system.
Long term marijuana usage is associated with long term memory.
Marijuana is a drug that has risks. You really need to stop comparing it to other drugs in an attempt to make it seem acceptable. It only makes your argument look weak.