Because they are "QUALIFIED", "PROBLEM-SOLVER", "INTELLIGENT", OR "FORWARD THINKING"? that happen to be "YOUNGEST", "FIRST WOMEN", "FIRST BLACK", "FIRST LGBT+" UNLIKE the GOP.
you never see the GOP stray too far from OLD WHITE GUY. You get the occasional white woman. Young white guy. Maybe even an old white woman. But the demographics of the GOP doesn't jibe too close with US demos. The Dems are closer to reality.