Again, based on what? I think an issue here that people are not considering is that the perception regarding illegal drugs is seriously skewed, as we usually only see the most extreme cases of drug abuse, as those who are in relative control of their use, won't be noticed, as they are using in secret due to the law. While in case of alcohol use, everything is done in public. Hence the perception that it is easier do drink in moderation than it is to use other drugs in moderation.
A person using coke every now and then, won't do so publicly. Those who drink do. The same with other drugs like heroin and so on. Once you enter social circles where the use of drugs like ketamine, coke, heroin and so on is somewhat normalized, you see what I mean. My sister, as an example, works in advertising. The amount of coke that is being used in this industry is stunning. And many of the users will never have to check into rehab. Many of them will just stop using at some point. And some will lose everything because of it. Pretty much like with alcohol.
The irregular and not deadly or completely self destructive use of drugs other than alcohol, tobacco and cannabis is mostly invisible and happens behind closed doors. It completely skews the public perception of the risk involved in certain drugs.
I do however realize that the harm from alcohol partly stems from how normalized it is. That would likely be different if it were treated like other drugs.
But from everything I've read on the topic so far and regarding basically every method to try and rank these drugs I have seen yet, the outcome is usually the same: alcohol is among the worst or the worst.
By the way, I'm really not trying to downplay coke and similar drugs. I don't use them (tried a very small amount of coke once and hated it) and I would never advise to use them. My point is that alcohol really isn't any better and people still don't realize how incredibly harmful it is. And I think people especially don't realize how harmful small amounts of alcohol already can be. The alcohol lobby has worked wonders to try and convince people that regular use of alcohol in moderation won't be harmful, while in reality it is one of the main causes of cancer.
https://www.hhs.gov/sites/default/files/oash-alcohol-cancer-risk.pdf