Which drugs are you talking about? There's a wide range here; something like LSD is not as dangerous as, say, methamphetamine or tobacco. Also, you're ignoring

Which drugs are you talking about? There's a wide range here; something like LSD is not as dangerous as, say, methamphetamine or tobacco. Also, you're ignoring the possibility that the "unwholesomeness" of their lives, and general propensity for failure, caused their regular drug use, rather than vice versa. It doesn't sound like you're being entirely honest in your reasoning here.