We don't know what it really was because they did not reference where, if in any post, it came from.
If the phrase was the comment of a Freeper, then it would be very easy for O'Reilly to provide the link for it.
However, Bill O'Reilly's research of Free Republic probably lasted all of 20 seconds while looking over the shoulder of an intern showing him phrases out of context.
I predict that there will be no link provided to the "I Hate Blacks" phrase because that link will lead back to the headline of an article published by SFGate.com referencing a column by that name in a newspaper that was being "assailed".
Since providing that link will make Bill O'Reilly look like a fool, we should not hold our breaths waiting for them to provide that link. They never will.
As I said, "All the News that is Fit to Fake".
I would not be surprised if O'Reilly reads this post and then spins it to report that a Freeper named "Polybius" posted "I Hate Blacks" three times in a single post.