It is shortsighted, in the sense that it’s about a third as long a fence as it needs to be (and no funds have actually been allocated for its construction).
If the United States need more immigrant labor from an economic perspective, or want to help Mexicans from a humanitarian perspective, then those are the debates we should be having. Whether or not to look the other way at continuous and flagrant lawbreaking is another.
Right now, those who come here are self-selecting lawbreakers. The scrupulous ones stay home and are poor, while those who are willing to take advantage of others get the benefits.
We end up with a population in the US that has no respect for the law, and no respect for the government, who have their noses out of joint about being second-class “citizens” and (in most cases) having to sneak around and keep a low profile. Increase the quota for legal immigration if necessary, but the current situation is untenable.
If the Mexicans and their government put the same energy into building Mexico’s economy as they do into sneaking people across the Rio Grande, everybody would be better off.
And the Berlin Wall was built to keep people IN. There’s an enormous difference between walls to keep people in and walls to keep people out.