The makeup of the US government does not reflect it's population. Harris wasn't the first female VP candidate to run for a major party. Geraldine Ferraro was the first, and Palin also ran in 08. Being a minority candidate doesn't mean they are qualified, but the lack of diversity in the US government is a huge problem. About 50% of America are women, and a large portion of America is not white. That's not represented by our government. Those firsts are important.
That's fair enough, I just think if it were me I'd be thinking 'geeze can I just be VP like every white man before me?' - but who am I to whitemansplain how she/people who feel affinity should feel :)
My comment above though was mostly just that from that quoted paragraph I was pretty confused, if I now understand correctly it starts with more specific 'accomplishments' (if finally getting that representation can be called one) and then generalises massively to a much broader category, in a vague way that makes it sound like nothing or more specific than where it started.