Tetchy subject. I tend to be on the side of :
Yes, they are RESPONSIBLE for their addiction, but the resources should be offered for them to get out. You cant "force" someone out of addiction. They have got to make the choice.
They shouldnt be left out to dry, but they shouldnt be pitied/treated like they are helpless against it.
An interesting note, there are chemicals that are said to "remove" addictions (of certain kinds). And yet they are rarely given to addicts, unless the psychiatrists/psychopharmacologists are convinced the person "wants" to be rid of the addiction. Because simply removing the chemical dependency doesnt remove the psychological one.
Now, I wont deny the desire to help someone in whom you have a strong emotional investment (family, very close friends). You can stand by them and try to help them out. But without that investment first hand, there is no reason for someone to help out someone who doesnt want to help themselves.
I also wont deny that certain genetic factors (alcoholism runs in families) and societal factors (certain societies drink a lot more than others, peer pressure) make it easier to become addicted. But that does not excuse behavior that harms others.
It's a convoluted situation, mired in the problem that addicts hurt others as much as themselves. A mere internet discussion cannot clarify the issue.