I am not sure that the analogies work really well. Having lived in a city that was --at one time-- the most dangerous in the world in terms of homicides, I can tell you statistics lie. Even in the days with 10-15 executions a day, Ciudad Juarez loved to point to the rate of crime against INNOCENT victims in places like Michigan or New Orleans.
Statistics only go this far, but there is an underlying danger in many places in Mexico. It is not so much the danger to be killed by a group of drug lords or held for ransom, it is the sure LACK of protection and rights for young foreigners (and especially girls) in cities that have very loosely controlled police forces.
Even if you happen to find trouble in one of the multiple crime ridden places in the US, you have a reasonable chance to find the police on your side. Nothing could be farther from the truth is most places in Mexico, and especially in the more remote states. Police often work hand in hand with the most corrupt parts of the government and the organized crime.
If something happens to one in Oaxaca, where will you go turn to? One should really inquire what the safety net consists of on a 24/7 basis as opposed to pay heed to distant stories of a better and safer past. Mexico is full of wonderful people who would give their shirt away to strangers, but that does not limit the corrupt and violent forces that are at work. One only has to look at the teachers’ unions work in the past months: those are infiltrated by violent leaders who have nothing to do with education or working in schools. They are cockroaches and, unfortunately, they dominate the scene.
And, regarding statistics, one does not need to look farther than the laughable State Department warnings. Yep, stay close to Acapulco or Lazaro Cardenas sounds like good advice until one knows how to read a local newspaper or listen to the radio.