What does it mean “Taken Over”? What is the goal of these people? What is their strategy?
What is the goal of these people?”
To open up an unobstructed lane of access for their drug shipments & mules.
The USA knows the value of military bases on foreign soil. Zetas obviously know it too. They just don't plan on playing nice by paying for the lease.
For them, the value of bases on the US side of the border is huge. They need safe areas to receive and send shipments, launch and land airplanes, park and maintain US-licensed vehicles, store materials, weapons, and so on.
With all the encouragement that is gushing from the White House, the invaders expect no resistance. The owners "evacuated" themselves, and the LEO is "studying their options." Perhaps in a few years the police will be learned enough to do something, barring a lawsuit from the federal government (of this country - must mention that, since these days foreign countries seem to have legal standing in US courts, but US citizens don't have any.)