There are a few factual inaccuracies with this piece. Firstly, as others have commented, trump has denounced the KKK and white supremacy on numerous occasions. Secondly, the proud boys have no ethnic requirements to Join, and as a result they are a multiracial group.
Thirdly, in the context of the recent riots, which were spurred on by the deaths of George Floyd and breonna Taylor, it’s pretty obvious that if there were any prominent white supremacist groups, they wouldn’t be rioting that a minority was killed. Instead, it was antifa and BLM rioting in the streets, which nobody is asking Biden to denounce?