The vote speaks for itself, in a way.  While the majority of members may not be bigoted/uninformed*, the GOP is increasingly electing bigoted/uninformed politicians.  This happens only a couple of ways- either the majority of the party are bigoted/uninformed, or a large enough minority of the party is bigoted/uninformed and is being aided to ascendency by enough of the rest of the ACTUAL membership majority not voting.
The end result is the same: bigoted/uninformed GOP politicians are receiving a majority of GOP votes cast.  The GOP's "brand identity" is becoming tarnished in the minds of those targeted by those politicians, and in the minds of those sympathetic to the issues the targeted people face.
And like the state of affairs that created the problem has few root causes, the solutions are equally few: the non-bigoted majority must exercise its political rhetoric and muscle within the party, or they must break away from what the GOP has become and create a new party free of such influences.  Each path has its own benefits and hazards.
	
	
		
		
			Most Republicans I know treat Duke as an insult to the party. 
		
		
	 
Then, as pointed out in articles like this one, it is time for you and those you know to become more vocal and/or active.
http://www.thedailybeast.com/articl...-gop-really-is-becoming-the-racist-party.html
While The Donald has been critical of Duke in the past, his CURRENT response to obvious reported support from Duke and his ilk has been mild.  For whatever reason, instead of forceful repudiation, support of the racist element within the GOP is welcomed with the promise to do so "if it will make (people) feel better."
At the very least, it is having your cake and eating it.  He can claim he is still against Duke's philosophies while still receiving his support.
And he isn't the only GOP candidate playing that game.
Look at John McCain for an example of why this matters.  For DECADES, he vocally opposed and warmed against the GOP becoming too entangled with the religious right.  He even got in verbal sparring matches with several of the big name religious leaders, like Pat Robertson.  But his words had little effect- the GOP liked the political victories close relationships with that branch of conservatism brought and cultivated a closer relationship.
But when McCain's final presidential run was floundering and he was last in the polls and fundraising, how did he right his sinking ship?  He groveled at the feet of the religious right, and even did appearances on shows like the 700 Club to boost his fundraising.
And that worked- money rolled in and he got the nomination.
Back to 2015: GOP presidential hopefuls are being soft with their responses to the racist element within the party.  Are there enough white supremacists to give a candidate a McCain-esque boost?  I don't think so; I hope not.
But unless the party gets serious about responding to those among them who are bigoted, that number is likely to grow.  At the very least, it will increase the "brown flight" away from the GOP at a time when America's demographics are becoming less Caucasian every year.
* I say bigoted/uninformed to allow for the possibility that the person in question may not realize the bigotry inherent in particular language or legislation