Who here will admit that they don't actually care about whether or not the wall would impact illegal crossings, or even about the amount of money it might cost the nation? That's not what it's about. It's about not letting a president as offensive as Trump get his way with anything. Admit it. You think he's a horrible person and you simply won't play nice with somebody like that.
I didn't care about the wall until it became clear that Trump was appealing to the basest hatreds that people hold. Here was a man with absolutely no idea whether a wall would work or not, or be a total waste, and who couldn't care less. He only cared that he could use it to appeal to a bunch of simpletons with deeply held fear and hatred. Remember, this was his same approach to replacing the ACA and how did that end up? "Nobody knew healthcare could be so complicated."
Should the day come a President that can be trusted comes forward and says "hey look, we actually do need a wall," then I may change my mind. Until then, I'll put my trust in better technology at the border, barriers where needed, placing more responsibility on employers to not hire illegals, and the like.