Because only the tiniest fraction of a percent of tourists overstay visas, and tourism is $1.5 trillion industry in the U.S. Denying tourists from entire count

Because only the tiniest fraction of a percent of tourists overstay visas, and tourism is $1.5 trillion industry in the U.S. Denying tourists from entire countries will result in a loss of jobs. You don't cut of your arm because of a papercut.