Frankly this is actually a bit encouraging. What I found disheartening was not so much that McCain didn't talk about immigration—that was to be expected,— but that the grassroots of the Party seemed to stop caring. It's better for them to be silenced, than silence themselves; and it seems like these young men have learned a valuable lesson about the Republican establishment.
It is also worth noting that McCain's platform calls for "Setting clear guidelines and objectives for securing the border through physical and virtual barriers," and campaigned claiming how important it would be to build a fence.