Decriminalization in Oregon decriminalized a variety of drugs like heroin and methamphetamine, enabling police to seize them. The speaker argues that drugs should not be generalized as one category, as substances like caffeine and alcohol differ from heroin and methamphetamine. The speaker proposes categorizing drugs based on their impact on society, with substances like alcohol, caffeine, and marijuana considered acceptable, while drugs like fentanyl are highly detrimental to individuals and society.