You can’t condemn white supremacists, because there are no white supremacists.
When most people think “white supremacist”, they think of neo-nazi skinheads, or the Klan, or David Duke, or the Aryan Nation. And those people are all terrible hateful people, and worthy of condemnation.
But that’s not what a Leftist means when they say “white supremacist”. When they say white supremacist, they mean all of us. Anybody that loves America, puts American values and interests first. Anybody that wants to stop immigration from countries that hate us, and wants all illegals to go back where they came from. Anybody that believes in hard work, thrift, fair play, and wants a better life for their children. Anybody who believes the Left is evil, and hates America and by extension them.
When they keep demanding that Trump “condemn white supremacy” and he has, lots of times, what they really want is for him to “condemn all your voters and apologize for ever suggesting that out of control illegal immigration is wrong and repent and do penance.”
This Trump will never do. Everything the Left stands for, everything the Left believes, is racist. They hate white people. They hate Christians. They hate America as founded. They hate men. They hate married people with kids. They hate normal, everyday hard-working Americans.
They are the party of hate, division, and authoritarianism.
You can’t condemn phantoms, especially when the Left sets themselves up as the sole arbiters of who is and who is not a white supremacist. But you can condemn Leftist ideals. And Trump did that in his debate admirably.