Knowing what it like in the Bay Area the Vice President’s pre-adult years were just so typical. Mixed race kids are the rule rather than exception. Her being raised “black" is a ridiculous assumption. She was brought up in as a privileged child in neighborhoods where color doesn’t matter as it should be. Just another prosperous kid born to a hard working Indian mother. Hardly the archetypal “black" experience in America.
President Biden picked her for Vice President because she also ran for President and she is black. Having known her from California politics I didn’t even know she was black. Anyway he was able to check off a box with Senator Harris. He has given her a portfolio of impossible tasks. Since he was also Vice President at one time you have to assume he knew what he was doing.
Notice he hasn’t come to her rescue after her recent trip to Central America. He is damned if he does and damned if he doesn’t. He can’t be the “man" and save the damsel in distress either. He is banking on the fallback that the Vice President is handling the issue.
You could look at it another way. The Vice President asked for the job as the President’s representative for the Border Crisis. Being black, she handily fits in as part of the oppressed class like the immigrants. She may have thought she could make her reputation as a future President by positive action on the border crisis. It is projected two million people will cross the border illegally this year. We will see how that works out.