Although I don't partake in smoking anything I realize close to 60% of the population is in favor of legalizing marijuana on some level.
If anything politicians are late to addressing the wants of the majority.
Every generation is more "socially liberal" than the previous one.
Generation X and Millennials didn't grow up believing just because marijuana was illegal it was worse than alcohol or prescription drugs.
They weren't exposed to propaganda movies like "Reefer Madness" blowing (green smoke), suddenly becoming violent, promiscuous, seeing the eye of stove on fire as a flower and other nonsense.
Their parents and grandparents are "Baby Boomers" the ones who launched the hippie lifestyle, "free love", "Turn on,Tune in, Drop out" movements. Marijuana to them was the equivalent of drinking beer.
Granted today's marijuana is much more potent than the "Baby Boomers" had they still view it as being safer than alcohol.
Last but not least marijuana has been documented to have medicinal usefulness regarding cancer nausea, glaucoma, bi-polar disease..etc
Democrats and Libertarians are often the first political groups in favor of social and personal freedom issues that defy traditional thinking when they realize the majority of people approve.
Pro-choice, Interracial Marriage, Gay Marriage, and Medical marijuana weren't known to be supported by conservatives.
I suspect Nancy is more in step with (the majority) than insane.