On Facebook this morning that seems to be the only thing people took from the debate - Trump refused to condemn white supremacy. Here is the answer I’ve been using - feel free to copy or improve it.

“What debate were you watching? Wallace asked Trump to condemn white supremacy and Trump said “sure” before the question was even done. Wallace asked if Trump would tell groups to stand down, and Trump asked for a name. Who do you want me to condemn? They said Proud Boys and Trump immediately told them to stand down just like Wallace asked. Don’t worry if that’s not how you remember it, I’ve got the tape right here https://rumble.com/vakfxx-biden-refuses-to-denounce-antifa.html“

You might also point out that on at least three other occasions during his presidency Trump has specifically condemned white supremacy https://www.factcheck.org/2020/02/trump-has-condemned-white-supremacists/

And I might even follow up by asking why Biden won’t condemn violent Antifa rioters and why nobody is asking him to. Or ask why is it that it took Trump coming into office to declare the KKK a terrorist organization https://nypost.com/2020/09/25/trump-to-designate-kkk-antifa-as-terrorist-groups-in-black-empowerment-plan/

Edited to add: here is a shorter version of the above "I can't believe you think that the president who last week declared the KKK a terrorist organization, who unrolled Biden's crime bill which put so many black people in prison, who brought black unemployment to the lowest number ever recorded, who has been nominated for a Nobel Peace Prize three times, and who has repeatedly made speeches condemning white supremacy is actually a white supremacist sympathizer. You're literally saying that Trump's words and actions as president do not carry as much weight as this clip where he again condemns white supremacists, but not as forcefully as you would have liked."