"As a society we have always outlawed drugs that can drastically alter perception"
Actually, in America nationwide drug laws began in the 20th century, and it had nothing to do with health or unknown effects. Opium was outlawed as part of a general effort to "protect America" from Chinese immigrants. Heroin was outlawed because a German company held a patent on it. Cocaine was outlawed because, according to the people in Congress at the time, it drove black men crazy and made it impossible to kill them with standard police-issue sidearms (also, according to an article from the New York Times just before cocaine was banned, Jews were selling it). Marijuana prohibition was principally driven by racism and as a form of regulatory capture by industries that competed with hemp.
LSD was discovered decades before it was outlawed and the effects were well understood before it was banned. LSD happens to be one of the safest recreational drugs; in fact, the biggest danger is the poorly regulated supply chain i.e. most "LSD" on the market today is not actually LSD (as with most drugs, the ban poses a greater health risk than the drug itself). The government conducted its own extremely unethical LSD study to determine if it could be used as a mind control drug (it cannot) and knew the safety profile long before the ban. LSD was banned because of concerns that it was contributing to the moral corruption of American youth (i.e. think of all those white teenagers out partying with hippies); in other words, it was viewed as a threat to the prevailing social order (probably not a coincidence that this coincided with the civil rights movement, which was a direct challenge to that social order).