From this:

Speaking to reporters in Phoenix, McCain said Hispanic citizens want America's borders secured and illegal immigrants to be treated humanely.

He added that low-income Hispanic citizens are vulnerable to losing their jobs to the lower wages accepted by illegal immigrants.

However, per this he acknowledged "that Latinos had been discouraged by the harsh anti-immigration tone during parts of the Republican primaries". There wasn't really a "harsh anti-immigration tone" coming from the previous GOP candidates, he's just playing the role of Howard Dean and making that up. And, it's possible to secure our borders, treat illegal aliens humanely, and avoid a harsh tone: we simply enforce the current laws. That will result in many or most illegal aliens returning home and reforming their own countries, which is the most humane solution of all. McCain is peddling false compassion, trying to pretend that allowing 14% of a country's workforce to move here is good policy.