They were killed by Mexican gang members, many of whom come across the border illegally to sell drugs or purchase weapons.
But the PC side is more worried about alleged "racism" than the actual body count, and ease by which the gangsters sneak into the US
You obviously agree with Trump that these many, many Mexican deaths and disappearances are a "good start" and will cut down on the rapists, murderers, etc. coming into the U.S. illegally from Mexico.
What right-wingers fail to understand is that the tremendous amounts of money made by drug cartels from narcotic sales in the U.S. will not be given up without a fight. This means a barrier like the Berlin Wall would be needed to just slow them down, stopping them is impossible. How many conservatives and neoconservatives would be willing to pay the massive expenses needed to build and maintain border security of this magnitude?
Congressional Republicans can't agree which segment of the population to steal the money from necessary to maintain the highway system. The highways are a major tool of the very rich and Big Business, used by them to maximize profits. If the House AND Senate Republicans have allowed themselves to disappoint their political benefactors for so long on this issue, they will have no qualms about ignoring the pleas of the conservatives and neoconservatives when it comes to border security. (Also forgotten by the right wing, the GOP does NOT want to cut off the source of cheap labor their friends in Big Agriculture, and others, need to keep profits growing.)
Throw into the mix that the border security demanded by the right-wingers is just too expensive for what it might accomplish. After all, how many members of the one percent or corporate officers are touched personally by violence caused by the murderers and rapists Trump mentions?
Only insignificant citizens (you know, America's working class) are affected, the important Americans are beyond the reach of the criminals from south-of-the-border. The Donald knows this, and like other Republican politicians, is simply building on the right-wingers' own fear, using it against them to gain their support. As if the conservatives and neoconservatives were not already afraid of their own shadows.