Many thousands of people smoke crack. Most (that's right, the vast majority, just as with alcohol) don't commit crimes.
When anybody commits an actual crime, either to support their bad habit, or as a result of engaging in their bad habit, then they are liable under the law.
Millions more people drink alcohol than smoke crack. In my experience, when you consider the abuse, murder, drunk driving, vehicular homicide, and violent crime which directly result from the use of the legal drug alcohol, it dwarfs the negative effects of all illegal drugs combined.
Neither crack users, heroin addicts, nor alcoholics deserve imprisonment simply for possessing or using a certain substance.
Contraband law is inherently Tyrannical, and always will be. The War on Drugs has nothing to do with justice. It's a hysterical overreaction, based largely on authoritarian propaganda, which does nothing to solve any of the underlying problems.
Prohibition does not work, with alcohol, guns, or anything else...