It's our demand that creates the problem and our policies that exacerbate them.
At least with these criminals it's not just about drug trafficking ---- many are involved in the murders of Mexican women in Ciudad Juarez --- they're just criminals who use the border for many of their crimes. They're involved with all kinds of crime.
Besides --- the WOD being fought against Americans is one thing --- foreign criminals coming to the USA to commit any kind of crimes is another. There could be an argument made that the USA government shouldn't interfere with your rights to use drugs -- but that doesn't mean the border should stay a free-for-all criminal zone. The Constitution doesn't protect the rights of Mexican criminals to do anything in the USA.