The Supreme Court is not and has never been a purely merit-based court comprised of the nine best-qualified jurists in the country. Choosing its members has always been a political process that by design has to meet with the approval of the Senate, and there are a number of factors beyond their experience and skill as a judge that are always taken into consideration. For example, there's ideology. Are conservatives wrong to always appoint conservative justices, or liberals wrong to always appoint liberal justices? There's also age, which is a particularly interesting one, because while there's no inherent conflict between searching for a qualified candidate and searching for one who happens to be of a certain race or gender, searching for an especially young candidate does have a tendency to rule out well-qualified ones. That's arguably what happened with Amy Coney Barrett; the Federalist Society (I won't bother pretending Trump had any input on the selection process outside of his final approval) almost certainly chose her mainly because they wanted someone young who could stay on the court for decades, which naturally led to the criticism that she wasn't qualified or experienced enough. Is deliberately choosing a black, female, and well-qualified candidate really so much worse than deliberately choosing a young, not-so-well-qualified candidate?
Something similar applies with the VP, which is nowadays more of a symbolic position than anything else (nobody thinks it's very likely that the president will die or resign, after all), and is typically chosen to appeal to voters as providing something that the presidential candidate lacks. Of course Harris being a woman and a person of color was key to her being picked as Biden's VP. I don't think that's inherently worse than, say, Mike Pence being picked as Trump's VP to cater to the religious right, who might otherwise have been scared off by Trump's sleaziness and long history of womanizing. Republicans and their identity politics, am I right?