From this article on Latin American reaction to the U.S. House of Representatives’ bill proposing a 700-mile wall to separate California, Arizona, and parts of Texas from Mexico:
“Comparisons of proposals to alter our border policies to the Berlin Wall are not only disingenuous and intellectually dishonest, they are personally offensive to me,” [U.S. ambassador to Mexico Tony] Garza wrote in a statement issued by the U.S. Embassy. “The Berlin Wall was built to keep its own people trapped inside, and was created by an oppressive authoritarian government.”
Democratic, exclusionary walls=good. Authoritarian, inclusionary walls=bad.