We have enough crime of our own without importing all the criminals from Mexico. Crime is one big reason there needs to be some control over the border --- Mexico doesn't do much about their criminals --- look at the over 400 unsolved murders of young women and girls in just one town alone. Why should those murderers who run loose in Mexico be allowed to easily cross the border and do what they like over here?
Is it necessary for me to explicitly state I am anti-illegal immigration? For heaven's sake, I am.
That is beside the point.
And btw, I have family and friends who work the border patrol, so I am not far removed from the topic.