That's an easy answer ... because parts of Mexico ARE just as dangerous as Syria & Somalia ... because Mexico is a sh!thole country.
http://www.breitbart.com/texas/2018/01/18/u-s-considers-parts-mexico-dangerous-syria-somalia/
The U.S. Department of State (DoS) rolled out a level-based warning system and issued "do not travel" advisories to five Mexican states - all for cartel violence. ...
The essential American soul is hard, isolate, stoic, and a killer. It has never yet melted. ~ D.H. Lawrence