You guys have to realize though, in a vacuum, non-intravenous heroin use could be less detrimental than even alcohol use. Heroin has never proven to be neurotoxic, like alcohol, amphetamines, and other stimulants, and is not toxic to any other organs, like alcohol and other drugs are to the liver.
The reason it's so fucked is because of its addictive qualities. Plunging a needle into your skin and veins over and over, and living the destitute lifestyle of an intravenous addict is what will kill you. These people forsake eating for this stuff, literally. Contract horrible things from shared/dirty needles.
If you have some self control you can very occasionally abuse it without a needle, like any other opiate, and be relatively fine.
Then you have crack and meth, which I think are more destructive than any other drugs out. they have the extreme addictive qualities of heroin AND are very neurotoxic.
I still think it's fucked though, people go way too far with this shit.