The pure rationalist loses something important.
> infinities cannot be compared
That's either a mathematically illiterate assumption or a very strange philosophical hill to die on.
> some tragedies cannot be averted
Sure. The question is what to do about the ones that can be averted.
> some decisions are impossible to make
> and "prioritization" is a distraction that forces choices when choices are not strictly necessary.
Again, the question is what choices to make when you can (arguably must) make them. Saying they're impossible is just refusing to take responsibility. You either do something, or you don't.
If you believe sanctity of all life is a solution, then I'm curious what you believe the problem is that such a belief solves.
I bet it's circularly defined as justifying the preservation of sacred nonhuman life? I'm not trying to be provocative just curious.