These are 2 separate concepts. Most value individual liberty at least on some basic level. But we can still feel sad when people make bad choices, with tragic results.
Of course, addicts and substance abusers are responsible for their own actions. But we can still mourn for them when they lose those battles.
Those concepts are directly related. If someone makes a bad choice and tells others to butt out of it because it's his/her body, when that choice produces such a result, why should someone told to butt out be expected do anything but butt out of that?
If you choose to do action (fill in the blank) and tell me to butt out when you're doing it, don't expect me to feel sorry for you when the results are bad. I'm not saying someone deserves it but sometimes people get what they ask for. There is a difference.