And yet so many people struggle with using alcohol in a responsible way.
Alcohol is, incidentally, the only household-name drug that can actually kill you from withdrawal. Believe it or not, even though heroin withdrawal is miserable, as long as the person is taken care of and kept hydrated, they won't die from it. That is not true of alcohol; a person suffering from acute alcohol withdrawal can literally die from the direct effects of the withdrawal themselves.
In a pinch, opiates can actually be used to help a person detox from alcohol and mitigate the life-threatening seizures (and the pain). Benzos are much better for this, though, and are more commonly used in medical detoxification scenarios.
I've taken a harmless dose of cocaine: I drank coca tea in the Andes. That this is harmless seems less controversial than either alcohol or cannabis.
It's in any case difficult to separate "responsible" and irresponsible use of drugs when deciding on policy. Either alcohol should be banned, or all the less-dangerous drugs should be legalized.
A person who likes to drink a cup of wine or a beer two or three times a week, and doesn't do so when driving, receives and causes no harm in practice (I know, there are studies about increasing cancer risks due to alcohol, but no more than with meat and other non-drug products). This is not true of cocaine, heroin or even tobacco, where there is no such thing as a harmless dose, and it is controversial in the case of cannabis.