Former Republican presidential candidate Herman Cain on Monday rebuked Chris Rock for "holding onto the past" because the comedian called the Fourth of July "white people's Independence Day."

Rock drew the ire of conservatives on Twitter on Wednesday when he tweeted, "Happy white peoples independence day the slaves weren't free but I'm sure they enjoyed fireworks."

"Slavery existed for 2000yrs before America," America's Right blogger Jeff Schreiber fired back. "We eradicated it in 100yrs. We now have a black POTUS. #GoFuckYourself."

On Monday, Cain told CNN's Kyra Phillips that he had faced discrimination while growing up, but suggested that slavery could not have been ended until after the U.S. declared its independence.

"[Your family] never really grasped the discrimination thing, did you?" Phillips noted. "And you never embraced 'African American,' that term."

"No," Cain replied. "I believe that one of America's greatest strengths is its ability to change. I'm not holding on to the past. I don't want to forget the past, whether you go all the way back to slavery -- even for a Fourth of July celebration."

"I think it was Chris Rock who made fun of the fact, 'Well, it might be Independence Day, but the slaves weren't free then.' Look at it this way, if America had not become independent, slaves might still be slaves."

Georgetown ethicist John Keown has argued that the American Revolution actually prolonged slavery in the U.S.

America declared its independence in 1776, but it wasn't until almost 90 years later -- after the Civil War ended in 1865 -- that the Emancipation Proclamation was finally enforced throughout the South and the slaves were freed. The United Kingdom, however, had passed the the Slavery Abolition Act in 1833, freeing most slaves throughout the British Empire 32 years before American slavery was ended.

Watch this video from CNN's Newsroom, broadcast July 5, 2012.