Fox furious?

I have read this article several times, trying to understand it. But some fine details keep escaping me, and the meaning of it remains hidden.

Relations between the US and Mexico today took a turn for the worse after George Bush signed legislation for a 700-mile border fence to counter illegal immigration into the US.

The move was universally condemned by Mexican leaders. Vicente Fox, the country's president, told reporters that the fence would not stop millions of Mexicans from heading north in search of jobs.

"It is an embarrassment for the United States," Mr Fox said. "It is proof, perhaps, that the United States does not see immigration as a subject that corresponds to both countries."

There must be some mistake, surely. I understand that every Mexican just born considers it his/her birthright to be able to cross the border with US unfettered. For some reason or other the fence pisses the Mexicans off.

On the other hand, that part of Mr Fox's speech about "immigration as a subject that corresponds to both countries" - wouldn't the fence keep the hordes of Norte Americanos away as well?

I am totally confused. Where is that universal confusion sign?

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