[stuartcr]

No, you just sound like a person that has all the answers.

Why is it illegal?

[robertpaulsen]

It, along with all the other drugs, were subjected to an eight-point test outlined in the 1970 Controlled Substances Act (Section 811. Authority and criteria for classification of substances) to categorize drugs.

Marijuana, with no medical use, was classified as a Schedule I drug.

A better question is why should society legalize marijuana? What have we to gain by the legalization of yet another drug?