It is very hard for me to take US State Department warnings with much more than the proverbial grain of salt.
The periodic warnings they issue for my city, Rio de Janeiro, are almost laughable. The would be except that people actually think that the entire country is unsafe.
There is crime, and it is a serious problem. By the way, do they issue nighttime prohibitions to enter downtown Detroit, Baltimore, the South Bronx and so on?
As it happens I have lived in 16 countries. In at least ten of them there have been travel warnings from the US State Department.
The only time in my life that I have been subject to a crime was in zip code 90274 (look it up).
During travel to places as diverse as Algeria and Zimbabwe, with many in between, zero problems.
That said there is no question that Mexico has a crime problem. Act accordingly and go anyway is what I do.
FWIW, due to family and business I often travel between McAllen, Texas and Monterrey, and often to various cities in Tamaulipas. I do so in US registered luxury vehicles (so far not in my Tesla). Never a problem.
I do not intend to be dismissive of risks; that would be stupid. On the other hand if I followed their prescriptions during my life I would have missed some of the most interesting experiences of my life. I avoid nighttime travel in many parts of the world.
No doubt we'll here more about this specific situation since Tesla now has Superchargers convenient to travel through and around some of those US Stay Department certified scarey areas. I'll go from McAllen to Monterrey right through Reynosa just as I have been doing for forty years, but now with better roads and a Tesla. I will travel during daylight hours too, just as I typically do.
NOTE: The preceding is not advice. Anybody thinking about taking my advice should consider that I lived in and drove all over around Lebanon, Yemen and Iran and adjoining countries. Of course there have been lots of others. It is plausible that my risk tolerance might exceed that of the typical NA Tesla owner.