I’m definitely a fan of exploring the ‘virtual’ wall idea.Depends of if you're talking bio soil crust or a jaguar. Scavengers seems to be doing rather well.
But I get you're point about the impacts that illegal immigrants have. I don't think anyone questioning the wall means to compare the status quo with a wall. Everyone generally agrees that illegal immigration needs to be addressed, but a physical wall is certainly not the answer. It has never proven effective in the 1000's of years humans have tried to use them to keep people out.