I know that in my own experience I grew up thinking that way. When you truly accept that we today are not smarter nor necessarily more 'enlightened' than the people that came before us it opens your mind to the lessons of history in a very real way.
>After all, if we cling to this primitive idea that an addictive substance must be eradicated, and if we live in a world in which sex and food are considered addictive, where does that leave us as a species?
Have you considered that this "primitive" idea comes up over and over again among great thinkers and writers throughout human history because there's something to it? Do you think people today live happier, more fulfilling lives because food is superabundant to the point of excess and sexual proclivities are uninhibited?
Why are you so sure?