But I would choose one broken leg, if that would mean that the total amount of two broken legs would go to zero then.

Creatures somewhere in existence are going to face death and severe harm for the foreseeable future. This view then seems inert.

In another words. I would vaccinate everybody (the vaccination causes discomfort) to eliminate a deadly disease like Ebola which kills few.

What would you do?

There are enough minor threats with expensive countermeasures (more expensive as higher reliability is demanded) that this approach would devour all available wealth. It would bar us from, e.g. traveling for entertainment (risk of death exists whether we walk, drive, or fly). I wouldn't want that tradeoff for society or for myself.

I would endorse choosing a broken leg for one person if that guaranteed that nobody in the world had two broken legs, certainly. This seems to have drifted rather far from the original problem statement.

I would also vaccinate a few billion people to avoid a few hundred deaths/year, if the vaccination caused no negative consequences beyond mild discomfort (e.g., no chance of a fatal allergic reaction to the vaccine, no chance of someone starving to death for lack of the resources that went towards vaccination, etc).

I'm not sure I would vaccinate a few billion people to avoid a dozen deaths though... maybe, maybe not. I suspect it depends on how much I value the people involved.

I probably wouldn't vaccinate a few billion people to avoid a .000001 chance of someone dying. Though if I assume that people normally live a few million years instead of a few dozen, I might change my mind. I'm not sure though... it's hard to estimate with real numbers in such an implausible scenario; my intuitions about real scenarios (with opportunity costs, knock-on effects, etc.) keep interfering.

Which doesn't change my belief that scale matters. Breaking one person's leg is preferable to breaking two people's legs. Breaking both of one person's legs is preferable to breaking one of a million people's legs.

In another words. I would vaccinate everybody (the vaccination causes discomfort) to eliminate a deadly disease like Ebola which kills few.

What would you do?

I don't think you understand the logic behind the anti-speckers's choice. It isn't that we always oppose the greater number of minor disutilities. It's that we believe that there's an actual judgment to be made given the specific disutilities and numbers involved -- you on the other hand just ignore the numbers involved altogether.

I would vaccinate everyone to eradicate Ebola which kills few. But I would not vaccinate everyone to eradicate a different disease that mildly discomforts few only slightly more so than the vaccination process itself.