'Legalising' doesn't mean 'easy to get'.
Cigarettes and Alcohol are highly addictive and deadly too but society has decreed (rightly or wrongly) that they are socially acceptable or just too difficult to outlaw.
spamspamspam should IMO be legal, the same way as those 2, with the same restrictions on age and availability.
Heroin is a strange one. One can easily work, live, contribute to society etc. while one is addicted. Also, unless you OD on it, you can easily make a full physical recovery once clean. The main problem with Heroin addiction is the quality of the heroin and the crap it's cut with (including sand, rat poison etc.) and the fact that junkies share dirty needles and contract Hep C & HIV.
Ecstacy and Cocaine are also adulterated with god-knows-what muck too (including Heroin), and makes the use of such drugs very risky behaviour.
Heroin addictions are treated with Methadone which is just as addictive, but socially acceptable 'because a doctor gave it to them'.
If Heroin was licensed, quality controlled and administered to addicts (the vast majority of whom WANT to come off it), in conjunction with a support program to help them clean up as they reduced their dependence, we would see a reduction in the amount of addicts in Ireland. Of that I am convinced.
The days of shouting the old mantra of 'lock 'em up, bleedin druggies' are gone and we should see that it may have started as a laugh but people quickly become a slave to Heroin and need proper help, not to be chased underground so they can OD out of the way of the nice middle-classes.