I would argue Biden is actually slightly right of center. Most democrats are. Progressivism is a about pushing the Overton window back to the center because right now, the acceptable positions in US politics is only center and right. The problem is thinking that if there's only two parties one must be left and one must be right. That's only relative to each other, not to political science."Left" and "Right" are always relative. In the U.S. Biden is slightly left of center. In Europe he would be rather far right. It would be rather useless if both Democrats and Republicans were classified as "Right".