You know, as much as I was on the fence with illegal immigration, I'm now in favor of controlling it after seeing the problem in Mexifornia. Not a very libertarian approach though.
Unfortunately most people outside the border area frequently aren't aware ot the extent, scope or severity of problems involved.
I believe that when reasonable people look at the facts in this rather complex situation, and consider it rationally, they will come to the same conclusion you have.
Notice how for months I have patiently been posting facts whereas a number of proponents of amnesty and open borders have engaged in ad hominem attacks?