Because she didn’t want to win.

You have to win a primary to be selected as a candidate

She didn’t grab Biden by the balls.
She waited.

racism and misogyny, among other things

Many American vote counting systems are suspect and flunk accuracy tests used worldwide.

Most American citizens who vote are totally oblivious or see no problem with that.

The question should be what kind of election was she participating.

But the question is really moot because socialism teaches us that the winners in fair elections are no friends of the lower 99% of the population. So even if she was allowed to win, it would not matter much. Less drama in the news, perhaps.

But fear not, the democrats will be allowed to win congress again next year, giving hope to millions.