I think we’re all talking past one another.
My assertion is that democracy creates the urban paramilitaries and that once they exist, they will seek out profitable markets to dominate so they get more funds. I further assert that there are immutable differences between ethnic and racial groups that will have a large effect on how violent the drug trade is.
The pro-legalization implicit assumption is that profits draw entrants and that black markets participants are violent due to the lack of legal recourse for disputes.
If my assertion is correct then decriminalization will do nothing to eliminate the para-militaries; they exist due to the alliances needed for democratic governments to function (someone has to run the vote banks). Evidence for my assertion is that prohibition was ended and the organized crime that it made famous persisted and the influence of those crime organizations only really faded when they were replaced by a different ethnic vote bank.