For someone worried about facts and statistics you throw around a lot of total bull____ without citing anything yourself.
All of my information has admittedly been theoretical. If you want to start talking about spouting off "fact this and fact that" then YOU need to cite it.
Since you're admitting that you haven't read the info, or which countries marijuana is decriminalized in, I'll give you some help.
https://en.wikipedia.org/wiki/Legality_of_cannabis
The summary is that many countries have decriminalized it to some degree, including : Australia, Canada, Belgium, Czech Republic, Finland, Germany, Mexico, the Netherlands, Norway, Portugal, Russia, and Spain.
Now, one would assume that if your theory were correct, the majority of those countries would have experienced a significant increase in crime after decriminalization, because far more people would be taking the drug. After all, those countries have a wide range of cultures, and almost every single one has greater public services, including more generous welfare (compared to living expenses), than America.
Since you now have the information at your hands, which of those countries have experienced a significant increase in crime?
I'll even help you out and link you to Canadian crime statistics.
https://www.statcan.ca/english/freepub/85-002-XIE/85-002-XIE2007005.pdf
They've been on a decline since 1991 and are the lowest they've been in the past 25 years.