Most people who drink are not alcoholics, no. But with a drug like Cocaine, the consequences of the equivalent of a few pints (i.e. a few lines) after work is much more damaging to the user and everyone around them. It changes people, mentally and physically in a much shorter time frame and with much more venom than an addiction to alcohol, which in the vast majority of cases can be controlled.
I agree, but I genuinely don't think people would just hit a few lines of coke after work purely because it is legal to do so. For example, cannabis use amongst the Dutch has dropped since it was legalised over there. If you want to be an irresponsible drug user, then you can be anyway. It's hardly difficult to get hold of drugs in this country, and if you have a regualr dealer then even less so. Perhaps cocaine available on a govt. regulated market could be made less addictive?