Ruth Bader Ginsburg was a historic figure for many reasons, and in some ways her impact and story was even more important than that of Sandra Day O'Connor, the first woman appointed to the US Supreme Court. The thing is, she would be greatly symbolic regardless of her story, just for the fact that in two centuries, she was only the second woman on the Supreme Court.
The people governing the United States do not reflect its population. It never has. We reasonably have put systemic racism at the front of the conversation right now, but systemic sexism is just as much of a problem. Of the 24 people at the top of the Trump administration, 21 are white, 19 are white men. In many ways, the split in gender is even more telling, since the math is obvious that half of Americans are women, but the US population is also 40% non-white. The US Senate has made some progress, but it's still 74% male, and a staggering 91% white. The New York Times recently wrote a "Faces of Power" profile that shows 80% of the 922 most influential Americans are white, from Congress to Hollywood.
People are fond of saying, "It shouldn't matter what race or gender they are, only that they can do the job." That's extremely naive and idealistic, but it largely illustrates my point: If this were true, statistically the body of the powerful would approximately reflect the population. Furthermore, no matter how hard one tries to suppress some amount of unconscious bias, it still gets in the way of empathy and representation. The systemic discrimination reaches into every part of society, and it's the reason that people of color are disproportionately poor and have lesser health outcomes. Those inequities don't get fixed without representation.
If you're a white person who is tired of talking about race, just imagine how tired you would be of it if you weren't white. The same is true of being any number of minorities when you are not afforded the same opportunities. We can stop talking about it when equality is real. Until then, it's important to be a part of the solution, not oppose it.