Is it their fault that the illegality of the drug causes the criminal market and the issues that arise from it, however?
Yes.
Alcohol causes countless deaths
So why do we want to add to that number?
Marijuana and cocaine are pretty harmless in themselves
No they're not. Marijuana is not the mild relaxant it used to be in hippy days. Super potent strains created over the decades track with psychotic and violent behavior (see Berenson, A. for details).
The problem with cocaine is that's its an open-ended addiciton... the more cocaine a person does the more they want to do, there's no off switch.
And... legalizing narcotics just incentivizes criminals to come up with ever more potent concoctions.... (see fentanyl zombies).
Poland's alcohol culture is horrific - like the way heroin addicts are portrayed in Hollywood movies
You are several decades out of date. At the extremes it's a problem but nowhere near as large as it used to be. Alcohol and tobacco are enough, taking a softer stand toward harder drugs just leads to an escalation in addiction and ever increasing costs in making and distributing narcotics.
Think of the trail of broken and dead bodies that made your 'recreational' cocaine possible.

1302113008_1.jpg