What is your opinion of Cleaning up our trashed border see 6-minute doentary on the clean-up?

Don't get it, sorry. America is a country of immigrants, that's the whole point surely? A couple of hundred years ago your own ancestors were sailing ships across the Atlantic trying to make a new life for yourself, and rapidly exterminated the native residents who had been there for thousands of years. Then you put a fence across what looks like a random bit of land in a fairly empty, arid environment and say 'no, sorry this is our bit of arid desert!' I just don't get the point.