The problem with saying legalization will solve everything is the legal industries, such as avocados, are subject to extortion by the cartels. So if you legalized drugs you'd just have cartels extorting the legal drug makers and have the same amount of violence and gang activity.

Some areas where the local militia has replaced the police now exist because the police are too demoralized, corrupt or scared to protect the industry in that area from extortion, so the industry creates its own security force by arming local citizens.

This makes a case for the second amendment. If the police are too scared to protect you, why not let people without a criminal record have guns and form a militia?

https://www.theguardian.com/cities/2017/may/18/avocado-polic...