Fox News anchor Martha MacCallum challenged Joe Biden’s senior campaign adviser on President Trump’s use of the phrase “Chinese virus,” asking why it’s a racial slur.

Symone Sanders joined MacCallum on Wednesday night to discuss the coronavirus and the former vice president’s campaign. MacCallum asked whether Biden and other Democrats should unite with Trump during the coronavirus pandemic and “give credit where credit is due.”

Sanders took the question as an opportunity to criticize the president for his use of the phrase “Chinese virus.”

“A leader has to lead from the front, and so what President Trump came out … and some of what he said today was good, but the reality is he also stood at the podium and called the coronavirus, COVID-19, what I would suggest is a racial slur. It’s something that is offensive,” Sanders said.

MacCallum shot back: “Why? Why is that? Why would it be, to call it a Chinese virus when it originated in China? Why is that a problem?”

Sanders said that it’s a term “many Americans” find “offensive,” to which MacCallum jumped in to give the history behind the name of the MERS illness.

“Do you know why its called MERS, why is it called MERS, that virus?” MacCallum asked. “It’s called the Middle Eastern respiratory syndrome because that’s where it originated. So, this idea, you know, this sort of rabbit hole of, you know, getting into this whole issue of racism, I just think is so counterproductive to what we’re trying to do here.”

“I just talked to an amazing scholar on China moments ago who said absolutely China at the leadership level has tried to obfuscate and be everything but transparent since the very beginning. They lied and lied and lied about this situation,” she said. “Why is it not okay to recognize where it originated?”

MacCallum added during the segment: “Every thinking human being who looks at this understands that the reference is to the origin of the virus and also the leadership in terms of how that virus was handled in the country of origin. So I’m going to leave it there. I mean, come on.”