I agree with you.
Unfortunately, some libertarians would have a problem with this. They see
libertarianism as standing for "liberty with responsibility."
If we consider that someone addicted to drugs is acting irresponsibly, then
according to their definition this behavior is unlibertarian.
Warm regards, Michael
You are correct that destructive behavior is counter to the libertarian principle of liberty with responsibility. However, in my view, even more "unlibertarian" would be forcing someone to behave constructively if they do not wish to do so and are not interfering with my well being (interfering with my well being would include causing me to personally witness their mistreating someone as a result of their destructive behavior). I make a personal exception of my own children under my care; I would consider it my responsibility to ensure they learn to behave constructively.