Authoritarians want to punish those who harm no one
Most garden-variety authoritarians, commonly called "conservatives" and "liberals" in modern America, are probably pretty nice people. They don't go around attacking their neighbors, even though that is the reality of the philosophy they follow. They simply haven't thought their positions through that thoroughly. They are your friends and neighbors, your family and co-workers. Maybe even you. So why do they cling to authoritarianism?
I think some of it has to do with the emotional need to punish those who hurt others. That is understandable in a way. I'll address the "punishment culture" another time. The problem is that the same irrational emotions get co-opted and aimed at those who are harming no one, except, possibly, themselves. No matter how much their actions or behaviors may offend you, their private lives are none of your business. Until they initiate force against you.
Of course, some authoritarians cry out that drunk drivers, drug abusers, gun owners, or independent migrants ("illegal immigrants") could cause harm if they aren't punished first. Probably so. So could everyone else, since nothing is 100% safe.
If anyone causes harm to another, drunk or not, addicted or not, whichever tools he might use, regardless of his "legal status" with the government, he should be held accountable.
The crime that is often associated with drug use comes not from the drugs, but from drug prohibition. If sugar (and sugar substitutes) were outlawed tomorrow, criminal gangs would start fighting turf wars over that commodity, too. The price would go up, and people who wanted it would be forced to become criminals to get it. It's the same story every time prohibition is tried. Most drug users live perfectly average lives until they cross paths with the enforcers of prohibition. Then it is a downward spiral caused by the sanctions placed upon them and the public scorn. Often from people who are engaged in the exact same behaviors, but who have not yet been caught.
Most gun owners never shoot anyone, much less an innocent person. Yet anytime a violent attacker uses a gun in his attack, the gun owners who never hurt anyone are targeted by the government nannies. All this does is make future attacks more likely, and likely to be more deadly. It is complete insanity.
Independent migrants only become an issue because of their imagined drain on "tax supported" social services. Since ALL welfare is immoral and based upon theft, it should be ended, thereby destroying the argument.
None of these issues justifies meddling in the private affairs of your neighbors. Why not shrug off the heavy cloak of the control-freak and let yourself relax? You might be surprised how liberating it is.