In matters as complex as drug and drug prohibition issues it is important to begin by starting with the basics. For many people cannabis and its prohibition should be viewed as just one part of a broader social problem. To them, either the drug problem or even the entire social order is part of a larger moral disorder that needs to be reformed from one perspective or another. To these people dealing with cannabis separately may seem either too narrowly focused or even a betrayal of broader principles.
Many prohibitionists seem to be almost fixated on cannabis.
Often they spend more resources on cannabis than on other drugs. These people are disproportionably influential, especially in the US and France. These people dominate the drug education industry in the US to such a degree that most drug education is actually just heavy-handed prohibitionist propaganda. Unfortunately, this has the effect of undermining the credibility of real education, and may actually increase the use of hard drugs by young people. I have had many young people tell me that when they found out they had been lied to about cannabis they thought they had been lied to about other drugs as well.