Yes he is a bigot, a racist, a sexist, a fascist. Generally if you pick an ist that's considered bad, Trump is one.
He is also speaking to what the Republican electorate generally seem to want though. For decades now Republican candidates have been exploiting racists, albeit by dog whistles. See for instance the infamous "Hands" commercial -
https://www.youtube.com/watch?v=KIyewCdXMzk. There are many bad things which can be said about George W Bush, particularly in the way his campaign exploited anti-gay animus, but he was always quite clear that the US was not at war with Islam. But under Obama, the Republicans have rather gone off the deep end. To start with there was the whole "Birther" movement (Trump again), which tried to claim Obama wasn't really a US citizen and so couldn't be president. They have whipped up their own base into such fear of "their" America being lost that they've lost control of it now and it's coming back to bite them.
But Trump is merely the clearest examplar of GOP racial animus. Every GOP presidential candidate has said similar things, they're just not quite to open about it. Play a game of Trump or Not Trump at
https://www.hillaryclinton.com/feed/who-said-it-donald-trump-or-not-donald-trump/
A long-term (simplified) history lesson:
When the US was created, it included slavery in the constitution. As a federal system, not all states allowed slavery, but those in the South mostly did. Slaves famously counted as 3/5 of a person for purposes of taxation and representation. Later, the US Civil War was primarily over whether to allow slavery or not - the northern states said no, the South said yes, seceded and formed the Confederacy. The North declared war on the Confederacy, and eventually defeated them. It is noteworthy here that the US was led by Abraham Lincoln, who was from the Republican party.
However the end of slavery did not mean equality. While black people could no longer be kept as slaves, they were systematically denied rights. This morphed into the segregation of the early to mid 20th century, where there would, for instance, be one water fountain for white people, one for "coloureds", under the claim of "separate but equal". This was the "Jim Crow" era - while all men were meant to have the right to vote, obstacles were put in the way. For instance literacy tests for those who couldn't prove an education (namely black people) - you can try one at
http://www.openculture.com/2014/07/literacy-test-louisiana-used-to-suppress-the-black-vote.html
But this was not true equality, and the Supreme Court would rule that "separate is not equal". This was not a universally popular decision, and the president of the time, JFK, had to order troops to forcibly integrate the University of Alabama, against the wishes of the state's governor. Wallace and Kennedy were both Democrats, but the Democratic party was split between the southern "Dixiecrats", who supported segregation, and the northern Democrats who opposed it. Following JFK's assassination and the civil rights marches led by Rev Martin Luther King Jr, JFK's successor, Lyndon B Johnson, signed into law the Civil Rights Act. This required states with a history of racist laws to have any voting rights changes approved by the federal government. Johnson famously declared at the time "We [Democrats] have just lost the South for a generation."
Over time, the Dixiecrats migrated from the Democratic party into the Republican party, and they were by and large welcomed. Republicans who supported civil rights joined the Democrats. This is by and large the start of the polarisation now seen in US politics today. The South went from being solidly Democratic to solidly Republican, as it is now. This led to the "Southern Strategy", whereby a Republican candidate could win by appealing to the racism of the South. And should you think that that is a long-gone memory, George W Bush used the same method, but appealing to Southern homophobia.
In the past few decades, outright racism has been replaced by "dog whistles" - phrases used as code instead of saying what you actually mean. In recent years, this has become more anti-Muslim and anti-immigrant.
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The scary thing is that he might actually win. He won the Iowa caucus quite securely (with 33% of the overall vote). I can only hope that, if the loony party in America do select Trump as their candidate, that not only will just about anyone with a democratic leaning vote against him, I suspect a huge number of Republicans would do likewise.
Sorry to correct you, but the Iowa caucuses aren't until January. Trump has however been leading polls nationwide and in almost every state, including the recent one you cite where he was at 33%.