This kind of superficial analysis is at best specious and misleading.
"They ran on progressive policies" is not an analysis. It's a vibes check, and a poor one at that. Harris is a good bit to the left of Obama and Clinton's platform was a _good_ bit to the left of Obama's. Also Obama and Biden were _both_ attempting to reach across
It starts to look like "ran on progressive policies" is code for "I liked them better" rather than an actual statement of their actual positions.