I have no idea about Harris history but this seemed like such a biased headline and gossipy article I did a little digging about who the Washington Examiner is. Apparently it's a right wing paper owned by a billionaire mega donor to Trump's campaign.
Harris could easily be the most unpopular VP only because she pisses off both sides. To the right she's a black woman and that's plenty to hate her. To the left, she's a statist cop who put plenty of poor people in jail over tiny drug crimes. As the DA of San Francisco and AG of California she played a typical neoliberal role: executing conservative policies with flowery liberal verbiage.
Progressives don't like her and the DNC doesn't listen to their progressives often. She's definitely a sore spot.