Idk, but I remember the bogus argument that legalizing weed will reduce how many people use it by removing the "forbidden fruit" appeal.
edit: here's the comments section https://news.ycombinator.com/item?id=35788120
The hypothetical comparison like a decade ago was the number of users before legalization vs the number of users after. Every study I can find showed a sharp increase in usage in states that legalized it. If usage actually fell in '22, I doubt it came anywhere close to reversing the trend since legalization.