The problem of illegal migrants from Central and South America is directly related to the global economy, which the US plays the largest role in.
Everything from US farm subsidies to tariffs to illegal wars causes an inordinate amount of poverty and death in other countries. In the case of Mexico, we also stop the Colorado River from flowing into what once was verdant farm land. Migration has been the catalyst for growth in human civilisation since we first climbed out of the trees. Read Guns, Germs, And Steel by Jared Diamond if you don't believe me.
If you and your wife and children were starving and saw abundant wealth and waste in the country next door you would pack your bags tonight and migrate north tomorrow. The US is a nation built by immigrants, for immigrants, and populated mostly by non-native peoples. Love it or leave it, at least you have the freedom to do so at any time!