Police in L.A. typically don't cite for fireworks.....they frequently just steal them, then take them home for their kids or go out drinking with their fellow cop buddies and blow stuff up.
As to marijuana, many drugs were criminalized by the control freak government as a way to lash back at counterculture. Cocaine posession/use was criminalized by the goverment who thought that it would produce "...superhuman, super-sexual negro cocaine fiends who would go on violent rampages and rape caucasian women and then kill caucasian men."
Marijuana was banned in some areas because they were worried that it was the end-game of those who used opium who would eventually end up using marijuana. The 1st state to criminalize it was Utah. Mormons who traveled to Mexico in 1910 came back to Salt Lake City with marijuana. The church was not pleased and ruled against use of the drug. Since the state of Utah automatically enshrined church doctrine into law, the first state marijuana prohibition was established in 1915.
I personally question the wisdom of anyone putting burning leaves in their lips and inhaling the combustion byproducts, and it seems rather bizarre to consume any drug knowing that it may cause you to loose control, but there are plenty of very pleasurable things to do with positiver health benefits without resorting to drug use, so they hold no facination for me.
However, to penalize people with stupid laws for using drugs while making other drugs like caffeine and alcohol legal seems hypocritical. Especialyl laws that allow people to abuse opiate derivatives like percocet, darvocet, oxycontin, then diazempams like ambien, soma, etc, as long as the physicians and pharmaceuticals get a piece of the financial action is the height of hypocrisy.
The upside to legalization is it would reduce drug trafficking violent crimes, home burglaries to support habits, etc and taxation revenue would be generated, with the downside is people would be killing other people via driving under the influence.
The war on drugs has been a total and complete waste of time, taxpayers $, cops time who could be fighting real crime instead, and has stopped drug use about as well as prohibition stopped alcohol use. It has resulted in a slow, steady and near complete erosion of your Constitutional Rights under the 4th and 5th Amendments.