This is true to an extent. Legalizing drugs wouldn't be a panacea against all their social ills. Consider all the problems associated with alcohol abuse. It is implicated in a large percentage of date rapes and domestic abuse situations, traffic accidents and deaths, gun and other accidents (falling off balconies, etc.), lost jobs, and health problems. Some legalized drugs would have the same terrible consequences that they do today, but it's also true that the organized violence, the gang warfare, the Mexican kidnappings, would be gone. Well, Mexican cartels might still kidnap, but not to protect a drug trade.