NOTE: I think arguments about whether Donald Trump is a racist are a red herring. Obviously not all of Trump's supporters are racist, and any claim that they are is ridiculous and counterproductive. I don't really care if Donald Trump is a racist or not. I have issues with his policies, which is what I think people should be talking about.

Anyway, you asked for examples of situations where Trump has encouraged racial division, so I'm going to try to present some examples without any name-calling or hyperbole.

In addition to Gonzalo Curiel, he's made a few other remarks to which some people have taken offense.

The republican party is mostly pro-legal immigration. The official party stance is that legal immigration is good for business and increases the supply of labor. Trump distinguished himself early on in the primary by supporting a border wall between the US and Mexico. To explain his position, he stated that "Mexico is not sending us their best people." He went on to say that many people illegally crossing the border are rapists and murderers. Undoubtedly some people who illegally cross the border have committed such offenses, but it seems unlikely that a significant portion of the 11 million illegal immigrants currently in the US are rapists and murderers.

Trump has also voiced support for deporting all 11 million illegal immigrants in the US. This is much more hard-line than most other recent republican presidential candidates. The amount of money and resources that would be required to locate, round up, and deport 11 million people would likely be very high. Furthermore, many of these illegal immigrants have given birth to children since they got here, which makes their children legal US citizens. Trump has yet to clarify how he is going to deal with these split-citizenship families.

At another point, Trump supported a temporary ban on all Muslims entering the country. He initially said that we would ask people if they were Muslim, and if they said yes, we wouldn't let them into the country. He has since changed his plan to only involve stricter checks on people who are emigrating from war-torn areas.

I'm not entirely sure if this is due to Trump doing something to alienate African American voters, or if Hillary is just extremely popular with them (her husband was the president who signed Affirmative Action and a handful of other anti-discrimination bills). Regardless of the cause, Trump has very low approval among African American voters. According to an NBC News/Wallstreet Journal poll last week, Donald Trump is polling at literally 0% with African American voters in both Ohio and Pennsylvania, which are critical swing states.

There's also the issue of Barack Obama's birthplace. Donald Trump was one of the most famous proponents of the idea that President Obama was born in Kenya, and was therefore not a US citizen, and not eligible to be president. He demanded that Obama provide his birth certificate, which was eventually made public. Trump then argued that this was a short form version, and he didn't believe it was authentic. Trump has also stated that he does not believe President Obama graduated from Columbia University. Trump has distanced himself from these positions lately. He hasn't apologized or said that he no longer believes these things, but he doesn't talk about them and refuses to answer questions about it.