Anyway, no drug, not even alcohol, causes the fundamental ills of society. If we're looking for the source of our troubles, we shouldn't test people for drugs, we should test them for stupidity, ignorance, greed and love of power.

This quote suggests that drugs are not the root cause of the negative aspects of society. Instead, it states that traits like stupidity, ignorance, greed, and the love of power are the source of society’s problems. In other words, if we want to improve society, we shouldn’t focus on eliminating drugs, but rather, on reducing these negative traits in people.