Ability to make a judgment, to protect the body or honor, a quality for humans, is lost under the influence of drugs. There are two main features of Islamic prohibitions. Islam stops the wrong at the inception and not at the end. There is nothing like a safe drinking age or safe drugs to get high on. Most of the teenage alcoholics do not buy alcohol from the store but get it at home.
Islamic law makes no distinction between children and parents.
Islam blocks all the avenues to wrong. Therefore not only is illicit sex prohibited, but the casual free mixing of sexes, obscenity and pomography is prohibited. In the same context, not only is drinking wine prohibited, but making it, serving it, selling it, keeping it, or even growing grapes for the sole purpose of selling it to a winery for making wine is prohibited by the Prophet. The above verses were received over a period time. Muslim society was gradually prepared psychologically for the final prohibition so that when the last verse was received, they accepted it without any reluctance.