Drinking alcohol in moderation is fine, and most people do just that. Some don't and they cause so much damage, not just to themselves, but to their friends, families and, often, strangers. Effects of alcohol costs the NHS more than any other recreational drug. I believe it kills more people per year too.
Smoking a couple of joints may be equivalent to smoking 40 cigarettes, but if it's only done occasionally then that's not much of a problem either. Smoking from dawn to dusk is bad whether it's cigarettes or weed.
Doing dope or drink in moderation, imo, are pretty comparable.
I don't do drugs - including booze. I think that ALL drugs should be legalised. The quality will be regulated, you can educate people much more easily about the safest way to take any of them, from drinking with food to, well I don't know enough about taking crack or whatever to give an example. You can research the effects much more easily.
I have a friend who was a heroin addict in the 70s, disappeared for about 18m while being so, and then dropped it. He is now quite a well known and well respected actor - clean though. Coming off wasn't a problem, he just decided that he'd done enough and stopped. I suspect the majority of people would be like that with most drugs (and I include alcohol in that).
Legalising everything would ensure quality and safety, would get rid of this idea of 'gateway drugs' (which I don't believe generally happens anyway), would set a 'fair' price, would remove most peripheral risks, would be great for the taxman. The low level dealers could become self-employed businessmen (!), higher level dealers would no longer carry guns, and the serious dealers would either be out of business or become legitimate too, and all these people would pay tax.