This was not always the case. It was quite acceptable in times past, the not so far past, to regularly publish images that today would do more then raise eyebrows. As the offspring of a holocaust survivor, it is most logical for me to address the issue of racism from the standpoint of anti-semitism.
In the mid and early 19th century, Catholics and the pope were frequent targets. Prior to reconstruction, there was not too much in the way of anti african-american images or writing. After 1880 or so, the lid came off on all sorts of imagery that was, by today's standards, 10 out of 10 offensive. People like Richard K. Fox, publisher of tabloids such as Police Gazette, made no bones about his hatred for African Americans and Jews. E.C.Z. Judson (aka Ned Buntline) was an influential publisher, best remembered for "inventing" Buffalo Bill. He was also a supporter of the visciously racist "Know Nothing" party of the 1850's. Many of the humor magazines like Truth and Judge regularly featured racial parody. Probably the worst of all was Judges Library, an offshoot of Judge whose monthly issues were often wholly devoted to one or another minority group, full of the most offensive jokes and cartoons imaginable. No group was spared, Jews, Italians, Irish and African Americans were regularly portrayed in a most offensive light, obviously appealing to the basest elements of American society and fueling prejudice and bigotry for many future generations.
Things calmed down a bit after 1920 or so, but subtle and, at times, not so subtle, writing continued. Major publishers, like H.L. Mencken, did little to hide their anti-semitic views and, of course, Henry Ford's Dearborn Independent was little more than a rag to promote Ford's rabidly anti-semitic views about "The Protocols of Zion" and the jewish plan of economic dominance of international business, (while Hitler was still sitting in prison in the early 1920's writing "Mein Kampf", Ford was actively and widely spewing anti-semitic diatribe for all to see. If present-day Jews read more history, they'd be more likely to drive German cars before Fords). Ford himself became the brunt of parody in this cartoon by George Grosz published in the October 1932 issue of the satirical monthly, Americana.
Read http://en.wikipedia.org/wiki/Henry_Ford in particular the section on The Dearborn Independent, for further information on how Ford's views on Judiasm inspired and abetted Hitler.
Publications like John Greenleaf Whittier's National Era first published Harriet Beecher Stowe's "Uncle Tom's Cabin" that did a lot to stoke the fires of the Civil War and emancipation. The body of more tolerant journalism ultimately far exceeded the bad.
We've come a long way. This has been a pretty good year in getting us to a higher understanding. God Bless America, and all that she stands for.