With the United States heading into one of the most important and divisive elections in its history, as the nation wrestles with challenges like climate change, health care costs and immigration, the final question at Tuesday's Democratic primary debate centered on comedian-turned-talk-show-host Ellen DeGeneres.

Though Americans generally find DeGeneres' goofy dancing and good-natured pranks adorable, many social media commentators – and at least one presidential candidate – were not amused that CNN's moderators chose to ask about a celebrity rather than the more weighty issues facing the country.

"No, you are not closing with an Ellen question," tweeted one viewer.

"This question about Ellen is so stupid," tweeted another.

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DeGeneres was brought up at the political debate because she was recently spotted enjoying a Dallas Cowboys game while seated beside former President George W. Bush. The images of DeGeneres, who is a lesbian, yukking it up with Bush outraged some LGBTQ-rights activists who remembered his opposition to gay marriage. Others criticized DeGeneres for playing nice with a man they consider a war criminal for the 2003 invasion of Iraq.

DeGeneres addressed the controversy on her show, calling for more civility and explaining that she is "friends with a lot of people who don’t share the same beliefs that I have."

"We’re all different, and I think that we've forgotten that that’s OK," she said.

"In that spirit," CNN moderator Anderson Cooper asked the candidates to share a "friendship that you've had that would surprise us" and the impact that friendship had on them.

Former Housing and Urban Development Secretary Julián Castro was the first candidate to respond. He said he had valued friendships with people who think differently from himself, but he added that he thought it was possible to be kind while still holding elected officials like Bush to account.

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Later, Castro said the failure to ask more substantive questions was "journalistic malpractice."

He told MSNBC's Chris Hayes he'd hope to discuss the rising problem of homelessness in the U.S.

"But we talked about Ellen at the end," he said. "And I know what the point of the question was, but we keep leaving some of these huge issues that impact families off of the question agenda of these debates."

Castro and others were particularly perturbed that the candidates were not asked any questions about climate change.

"Three hours and no questions tonight about climate, housing, or immigration," tweeted Castro. "Climate change is an existential threat. America has a housing crisis. Children are still in cages at our border. But you know, Ellen. #DemocraticDebate."

Washington Gov. Jay Inslee – a former 2020 candidate who campaigned on the importance of addressing global warming – was also appalled that the moderators never took the time to ask the candidates about what he considers the most important topic of today.

"Not one single question about the climate crisis," Inslee tweeted. "This is the existential crisis of our time. Not one single question, and that’s completely inexcusable."

Here's a look at some other Twitter responses to the question about DeGeneres: