To see how the came to that conclusion. It's not like they hate brown people that speak funny, they have real issues that rightly or wrongly get blamed on immigration.
Hell, the KKK endorsed Trump and he didn't denounce them. So yes, there are at least some people who like Trump for his anti-immigrant views that base their support on racism. Based on what I've seen online and in person, there are quite a few of them. Maybe that's not all of them, and some or most are really just concerned about it as a law and order issue, but Trump made absolutely no effort to distinguish between the two. At no point did he ever make any statement that attempted to disassociate his views on immigration from racism, and he was called upon to do so throughout the campaign (like after the KKK endorsement).
Maybe he himself has more enlightened views on immigration, but he clearly couldn't care less if people were on his side because of pure racism. He stoked those fires over and over and over again. Maybe he's just incredibly misunderstood, but he sure as hell didn't make an effort to clarify anything if he was. That speaks volumes about his morals. If you're going to take a hardline stance on illegal immigration and make it a centerpiece of your campaign, it makes it that much more important to be very clear and explicit that racism is not a factor, if for no other reasons than to avoid getting lumped in with racists and to avoid indulging racist tendencies within your own base. Leaders are supposed to lead, and someone who wants to be president has a vastly greater responsibility to be a leader.
Also, the fact that the strongest support for Trump's anti-immigrant views came from the parts of the country that have the fewest immigrants doesn't help. I've known plenty of people who've lived their whole lives within 100 miles of where they were born, in parts of the country where they may not ever actually see a black person, much less anyone from the Middle East or Mexico. People in these homogenous rural communities form (in terms of numbers at least) the core of anti-immigrant sentiment, and yet they also seem to think that strange brown people sneaking into the country is the #1 issue facing America today. It's very hard to look at those views coming from those demographics and not think that there's at least some racism and xenophobia driving those views.
The KKK's official newspaper endorsed Trump, but according to CNN, Trump has disavowed the KKK (and David Duke in particular):
> Donald Trump issued a crystal clear disavowal Thursday of former Ku Klux Klan Grand Wizard David Duke after stumbling last weekend over a question about the hate group leader on CNN. "David Duke is a bad person, who I disavowed on numerous occasions over the years," Trump said on MSNBC's "Morning Joe."
> "I disavowed him. I disavowed the KKK," Trump added. "Do you want me to do it again for the 12th time? I disavowed him in the past, I disavow him now."
>Also, the fact that the strongest support for Trump's anti-immigrant views came from the parts of the country that have the fewest immigrants doesn't help.
Here's the kicker, why aren't people migrating to these places? They are lovely places that have had high immigration levels in the past. They do know that in other parts of the country those strange brown people are moving in and being more successful than they are in their own country though.
So, there could be a 30-year delay between a Mexican family's immigration into Texas, and a subset of that family and their descendants moving to Nebraska (random example). When someone is moving to a foreign country with a different language, and mostly populated by other ethnicities, it makes sense that families would usually start out in big border cities, and only gradually make their way to more and more remote, sparsely populated, and less diverse areas.