Because, fundamentally, when you say "admit she fucked up," you're not actually looking for... well, that.
Everyone here has said, on numerous occasions, that Hillary did stuff wrong. She didn't spend enough time in Wisconsin, she didn't tailor her message well to reach working class voters, she etc etc etc.
But you know what? She spent AGES in Pennsylvania. And she lost there. And she had tons of speeches about the economy. But they covered Trump's empty podium instead. And and and and and and.
What you're looking for isn't an "admission that she fucked up," or an accurate recounting of events. What you want is the catharsis from self-flagellation, though you might deny it. You want a reassurance that as long as the next Dem candidate doesn't "fuck up," then we'e assured victory, because FBI investigations and FSB propaganda campaigns don't really matter and our success is entirely in our own hands. But it's not. And we can't give that to you.