My take is, every country has borders and rules about who can enter their country and for how long they can stay. The whole world works that way. That's why we have passports and visas and green cards and asylum, etc. The world is a global community but we are made up of sovereign nations.
I have zero problem with anyone wanting to come to our country to make a better life for themselves. And, I don't care about the incoming nationality of those immagrants. That said, everyone should come through the front door. We shouldn't allow drug and weapons trafficking or known fugitives to cross into our country. That's why we have border crossings and customs. (again, like every other country in the world.)
At the airport, you have to go through the TSA line. There's a little valet rope that guides the line through the check point and you're not allowed to go around/over/under it. If you do, you get tackled by the TSA guards and police.
So, if there is a wide open area of thousands of miles allowing people to just go around the border checkpoints and its becoming a real problem, then yeah I don't see why we shouldn't have a wall. It makes sense. I don't think its racist, I think its prudent.