You want to see some people get treated bad? You should see the border control on Mexico's southern border. People die trying to get to Mexico so that they can cross to 'El Norte'. Mexico not working with the US to prevent border crossing is a pretty silly double standard; it's a testimony to Mexico's economy that it would nearly collapse without all the Yankee dollars, both legally and not legally earned, that return to Mexcio.
A wall that size doesn't make sense. It'll just get tunneled under, they already continuosly build smuggling tunnels for drugs and people. We need better enforcement of current employment and immigration law first, then a legitimate way for deserving people to become US Citizens. If the constant flow across the border is eased, it will be easier to enforce the border itself. Economically, it's gonna hurt some US businesses but the border situation as it is makes it easy for drugs and people from all over the world with all kinds of intentions to come in.