Why is Marijiuana illegal but alcohol is legal?

I read on a site that made really interesting points about this question.

"Logically speaking, it should be the other way around. Alcohol tends to make many people aggressive, leading to a variety of violent crimes, while marijuana does not. Alcohol is a central nervous system depressant, and leads to a serious loss of
coordination and motor skills. At larger doses, alcohol renders one completely unconscious. Drunk drivers cause enormous numbers of automobile accidents and deaths. Marijuana is not a central nervous system depressant, and while one probably shouldn't drive while intoxicated on anything, it simply does not cause anywhere near the loss of motor control that alcohol does, and is only a fraction as dangerous as alcohol in terms of driving. And, a large enough dose of alcohol can and will kill you, while the same is not true of marijuana."

Your thoughts?