Why do you have any faith in the outcome of this election, where the rules allow having only one political party count votes, unsupervised?
Political parties don't count the votes. Public employees/volunteers (who presumably vote for either or no party) do.
Could you not imagine a scenario where that could go wrong?
Sure, I can. I can also imagine a scenario where an asteroid crashes into the planet, or a scenario where a mad scientist brings dinosaurs back from the dead that escape into the North American environment, or that Trump is a Russian mole being blackmailed by Putin over a sex and urination tape from a Moscow hotel, or that an interdimensional rift opens and elves with magic powers try to conquer the world.
But you know what? When I judge reality, I prefer to use objective evidence rather than my imagination.
Also the link says "nobody was told to go home", but we have an affidavit from a witness saying the opposite, so who are we to trust, a statement made under penalty of perjury, or one that isn't?
Neither, because the flaws of subjective interpretation and memory are well-established concepts. That's a lot of what cross-examination is for, to test whether the witness's beliefs match up to other observable evidence, to test certainty, shake out potential errors or jog extra recollections. There is every chance the witness does not actually remember exactly what they were told, and/or mistook a suggestion as an instruction. Being mistaken is not perjury: perjury is deliberately saying something known to be false.
Next, as people are convicted of perjury, it proves people are willing to lie . So the argument that someone would not lie because they would go to jail is in fact remarkably weak. Lots of them do take that risk (and most of them probably calculate that they'll get away with it, and do).
As a side issue, it also begs the question that why did a Republican Party that was allegedly expecting massive fraud send in observers who were not aware of their fundamental rights to remain and watch any processing going on and challenge it at the time?