Some people use meth and opioids responsibly, but they very much are not the same as alcohol. Alcohol is a much safer recreational drug. Some people become alcoholics, but a higher percentage of people who try opioids get addicted, and addiction happens after fewer exposures.

The whole reason addiction is a problem is that it alter decision making, once someone is addicted. So you incur much of the moral responsibility the first time you decide to take the drug for fun.

And also, opioids are a curious example for responsible drug use, given how many people who used prescribed painkillers became addicted to them.