I drove over the border this year and spent several days in Mexico. I've also flown into Mexico. Everything was fine. I think your sources are misinformed.
What year vehicle were you driving; and where did you cross? I was driving a new car when I crossed at Laredo. I stopped at the Information desk, before I crossed to get a heads up on anything that I might need to know about. She strongly advised me not to take my car across the bridge. She said that the cartels have scouts waiting at the bridge, looking for valuable vehicles. They get on the phone and give a tag and description of the vehicle to those who will follow the vehicle, until the time is right for a carjacking. I crossed on foot. It didn't go well in Nuevo Laredo. I made that crossing alone. To make a long story short; I felt relived that I made it back out safely. I told my doctor about the trip. His father (Mexican American) lives in Laredo. He told me that I had made a big mistake crossing over there; that it just isn't safe there.
Did you fly to a resort destination?
Flying in is a different story, depending on where you're flying to. My girlfriend wanted me to meet her mother in Chihuahua at a family reunion. It was a costume party. She wanted to drive my car there. I told her that I felt uncomfortable about taking my car that deep into Mexico. She said that it was relatively safe in Chihuahua compared to Juarez. I stood my ground. She didn't have a car; so she suggested taking a bus. The trip was on. We went costume shopping.
I was excited about the trip, until she started giving me details about a past trip that she had made on a bus. She told me that the bus was traveling though an area where bodies lined the streets. The bus driver told everyone on the bus to get down on the floor, in hopes that any murderers would think that the bus was empty. She managed to make a safe trip. I can't work with that! She went to Chihuahua without me.
I crossed into Reynosa; and on the way back, Customs asked me the usual questions. He mentioned that it was a very dangerous place to cross. I told him that I was exploring the Mexico border; and asked him where a safer crossing would be. He said quite vehemently (as if he was my father) "there is no safe place to cross the Mexican border."
Who knows? Maybe he just watches too much FOX news. What could he possibly know about it; if he works there everyday; yet he's too afraid to set his foot on the other side. Maybe that's why these Federal Agents carry guns. Maybe they're just afraid of everything.
I had a long talk (maybe an hour) with a family, who spoke fluent Spanish in Progreso. They spent a lot of time visiting Mexico. At that time I hadn't seen much of Mexico; and I wasn't impressed with the prices, and the selection of products in Progreso Nuevo. I asked them where would be a relatively safe city, deeper within Mexico, that I could easily travel to from Progreso Nuevo, where I could find more authentic Mexican products. They strongly advised me against it. They said that even being fluent in Spanish, and with their experience with the Mexican culture; that they would be reluctant to move through cartel country; and with my limited ability to speak Spanish; that they would strongly advise against it.
...But who knows? Maybe you just know better.