The simple answer is enshrined in what occurred outside the Trump rally in New Mexico a couple evenings ago.
The angry mob caused mayhem outside of Albuquerque, New Mexico turning the city into a de facto Third World country. The rampaging “crowd” was made up of anti-Trump goons who were waving the Mexican flag while simultaneously burning the American flag.
Is there any question why “building a wall” resonates with the vast majority of Americans? But not Hillary, of course. She wants to “build a bridge” to Mexico, “not a wall” so we can see more American flags burned while illegals wave the flag to which they pay allegiance!