Is extreme deontology problematically impotent?
Yes!
Extreme deontologists hold the view that not violating rights is infinitely important. One shouldn’t kill a single person to save the world. This runs into the problem that it would seem to dictate immediate suicide.
If one does not immediately commit suicide then it’s possible that they’ll violate rights. Lots of ways this could happen.
1 Maybe they’ll change their view and become a serial killer.
2 Maybe they’ll hit a pedestrian. This is obviously a rights violation. If a person just drove their car into pedestrians for no reason that would be a rights violation.
3 It’s possible that they’ll do something horrific in a fit of rage.
4 It’s possible that actions they currently don’t realize are rights violations actually are rights violations. Maybe all the food that they eat is actually made of people who have been turned into food by a witch, but who are still conscious.
If the extreme deontologist holds that rights violations are infinitely bad then any risk of doing them can’t be done for any benefit. If one shouldn’t kill one person to save the world one certainly shouldn’t take a .0001% risk of killing one person to have a more fun life. Thus, these theories would demand immediate suicide in order to avoid violating rights.
Additionally, jailing an innocent person is surely a rights violation. Imagine that one person was a judge who only made a single mistake, but correctly sentenced trillions of people. On the deontologist account, this persons actions would be wrong—it would be better for there to be no legal system presided over by this nearly perfect judge, because they are violating some rights. This is deeply counterintuitive.
Maybe the deontologist thinks that doing things that will certainly violate rights are categorically distinct from, and worse than, doing things that will probably violate rights. This runs into a few problems.
1 It would hold that doing something with a 90% chance of killing someone 53222 times would be less bad than certainly killing one person.
2 It would hold that shooting at someone is less problematic than presiding over 100000000000000000000000000000 cases exremely well, because the odds of falsely sentencing someone in 1000000000000000000000000000000000 cases is much higher than the odds of actually killing someone when shooting at them.
These problems seem pretty damning.
"If one does not immediately commit suicide then it’s possible that they’ll violate rights. Lots of ways this could happen."
I'll turn this - it's highly plausible that accepting that your ideology mandates that you commit suicide could lead to even more rights violations. It may cause you to abandon that ideology, which means that you will violate rights or (even worse) become a utilitarian. It would mean that you fail and somehow cause someone else's rights to be violated. Perhaps you have adopted some ethical duties and killing yourself would violate those. It would take a pretty high level of certainty that you would violate someone's rights before that becomes an option. And I would say that one can probably have their rights violated if they are pressured into committing suicide. You might say that it makes no sense for someone to violate their own rights, but I would say that there's clearly a rights violation happening when someone is pressured to kill themselves, in that we should not be suicidal unless there's a good reason.
As for the specific examples - There's a 0% chance I become a serial killer, so I'm not worried about that.
Hitting pedestrians is bad, but doing it on accident isn't an infinite rights violation. I won't become a serial killer, so not going to do it intentionally.
Something horrific in a fit of rage - certainly possible,, though not probable enough to overcome the rights violations of killing myself or changing my mind after entertaining the thought.
As for the Witch, giving in to Pascal's wager is a rights violation.
Additionally, I think that your denouncement of discounting percentages is incorrect because deontology is concerned with the character of the act, not necessarily its ultimate consequences. So in the example of 53222 people or one person, you're directly weighing acts of murder against each other, so it would be appropriate to say that killing on average ~47,500 people is worse then killing 1 person. This is in contrast to the residual risks outlined above because the maybe inherent risk of doing something that slightly increases risks down the line isn't a violation of rights.
As for the second example of a person (let's say Person 7548986345) Presiding over a lot of cases, I think the above distinction solves the issue. Independently I think that someone getting a fair trial and a competent adjudicator is getting their rights fulfilled, even if they turn out to be innocent. Of course if someone later finds out they are innocent, they should be released.