Former Vice President Joe Biden denounced the "sophisticated" and "elitist" attitudes that he believes have overtaken the United States in the past 15-20 years, in a speech delivered to union leaders on Friday.

"There is no possibility any of those guys making millions of bucks on Wall Street, doing good work wherever they're doing it and doing very well, they could not function without the work you do. Literally. It's impossible to make the country function without what you do," Biden told his audience. "And don't you forget it. Don't you forget what you do."

Biden then called out American culture at large for abandoning its blue collar roots.

"We've gotten so damn sophisticated. We've gotten so damn elitist," he said.

Biden added that people who do menial labor deserve the thanks of the rest of the country.

"They make life work for us," he said. "And I hate they way things have changed over the past 15-20 years."

Biden served under former Vice President Barack Obama, whom many have charged as both too "sophisticated" and "elitist," including former presidential candidate Hillary Clinton, during her 2008 run for the Democratic nomination against Obama.

"You don't have to think back too far to remember that good men running for president were viewed as being elitist and out of touch with the values and the lives of millions of Americans," Clinton said of Obama during a rally in Biden's hometown of Scranton, Pennsylvania.

Charges of elitism have dogged Obama and his legacy since 2008, when the former president referred to working class voters in a demeaning way at a San Francisco fundraiser.

"It's not surprising, then, they get bitter, they cling to guns or religion or antipathy to people who aren't like them or anti-immigrant sentiment or anti-trade sentiment as a way to explain their frustrations," Obama said.