You’re right about Harding being less of a racist than Trump. In just about every biography of Harding there’s a really interesting story about him giving a speech on voting rights in the south to a crowd of 30,000 people (20,000 white and 10,000 Black). The audience was separated by a rope in the middle of the venue. When he strenuously condemned unfair and racists literacy tests for Black voters one side of the auditorium was dead silent and the other side cheered loudly (I’ll let you guess which side was which).
The comparison to today is less about the specific president and more about the political moment. There was a rise of violent racism in the United States in 1920 and there is a rise of violent racism in the United States today.