The problem of the presence of illegales never loomed large enough before in America for it to be seriously considered that born Americans carry around passports. America wasn’t France, it wasn’t Switzerland, it wasn’t China, it wasn’t any of those places which were habitually overrun enough that everyone had to “show papers, please.”
And the illegal problem may not have loomed large in your little section of America, but down here it is huge. You might be willing to allow Americans to be raped, robbed, and murdered just so long as you aren’t inconvenienced, but the rest of us can’t afford such an indulgence.