You're asking this question to the wrong people lol. Also, you talk about this like it happens anywhere in the world but the US.
In reality, what happens in Mexico and Brazil happens in other countries too but most of those other countries are pretty poor or have a significant involvement in narco or human trafficking.
You don't see this shit in Europe either. The question is silly because all the reasons are in front of you.
There are several reasons. Culture. Social structure. Education. Opportunities. Ancestry behavior. Environment. Etc.
In addition, to make it simpler, think of why would someone do these things to another person? What is the motivation?
Given all these are on a spectrum, it's fair to realize that given the different environment, it's hard to be on the far negative of the spectrum. Especially to be this common to make it an issue.