Re: I think he's discovered that it doesn't matter what he says
You are aware that the "Southern Strategy" theory is just that, a theory of the Left to smear the Republicans? And citing left-leaning Wikipedia on a political issue? Puh-lease.
Another cogent point is that the '64 Civil Rights Act was not a Democrat creation as many seem to think. See this Wikipedia article for more info. ;-)
Further, that act was much more popular among the Republicans than Democrats in Congress. See this Wikipedia article for details.
For a long analysis of the way the Democrats have somehow managed to smear the party of Lincoln as racists, see Kevin Williamson's article on the topic.