Playing russian roulette isn't responsible just because you don't get shot. There are many people who use it in moderation... until they don't. Until they make one too many "bit more won't hurt" type decisions. Or they lose their job or a family member dies or they just have a shitty day.

"responsible heroin use" is probably the stupidest phrase I've heard all day, and I've been watching CNN.

EDIT: And, by the way, calling a spade a spade and naming heroin as the scourge it is is not stigmatizing users.