Yes, you're right. Good Mexican food requires a certain simplicity that is impossible to describe. The very best --bar none -- tacos I've ever had were bought from a woman who operated a small kitchen under a stairwell beside the Clinda Roma in Guadalajara. If the best taco I've ever had since was a 6, those tacos were a 10.
The next best was a trio of women serving tamales out of a kettle on a street corner in Mexico city a few blocks from the Zocalo. Unfortunately, they served amoebas too, and by the time I could eat again two weeks later, I'd lost a quarter of my body weight.
Oh yuck. How horrible for you. I've never been in a third world country, and that's one reason why I wouldn't want to go.