Fair enough, but not everybody's Freud. The guy was exceptional because of his insights and intellect, as well as having a thirst for knowledge, which the cocaine no doubt exacerbated. It's a little bit easier to stay on the straight and narrow for at least a little while when you're so absorbed by your work with an unlimited supply that could be safely acquired. But even for Freud, it eventually caught up to him; he finally decided to quit cocaine for good after almost killing a patient while under the influence. You also have to remember it was easy to have an opinion like that before cocaine abuse became widespread and the consequences documented—it was only just starting to become noticed by the medical community around his time.