Now do democracy and voting. Or how about serving on a jury. Or serving on a school board.

By your definition those also must not be impartial and maybe that is a fair definition but what does it imply?

Do you similarly distrust democratic outcomes, jury decisions, etc.?

Would you prefer a trial by community notes or by jury.

Jurors do not self-select into jury duty, though some try harder than others to get out of it. So the effect is less.

Voters are partial to the candidates they vote for; that's why they vote for them.

I was able to get out of jury duty by saying I tended to agree with police. This was advice given to me by a friend in law enforcement.:.

Yes, it's not difficult to get out of. You could also get out by saying that you don't trust the police, or any number of things that might affect your ability to be impartial in the case before you.

It works quite well in practice. The unapproved notes are a bit all over the place in terms of bias and or being wrong but the ones that get enough votes to be shown are mostly fairly factually correct.