What if everyone thought that way is one big fallacy

A common argument raised against many good ideas is some variation of "if *everyone* thought that way, X would happen". For example, when I was young and indoctrinated with conservatism, I was taught to think, "it might not seem like my vote makes a difference, but if no one voted, the system would fall apart, therefore I should vote". This is just a blatant non-sequitur.

My decision is causally independent of everyone else's. Whether I vote doesn't affect whether everyone else does, so if it really is true that my vote is not an efficient way for me to create change, then I shouldn't vote, no matter what would happen if no one voted.

One version of the Wikipedia donation ad said:

If you donate just $2.75, the price of your Tuesday coffee, Wikipedia could keep thriving.

Dear Wikipedia admins, look I understand (from making non-scarce goods) the frustration of being a volunteer and not getting paid, but that's blatantly false. $2.75 will make no discernible difference. A truthful version of this would say "if *a whole bunch* of people donated just $2.75, Wikipedia could keep thriving".

Obviously, if one Y happens for each X, you can say that one X causes one Y, or you can say that a thousand Xs causes a thousand Ys. What you can't say is that one X causes a thousand Ys. That's what their ad said.

It's also exactly the argument I heard many people make for the COVID-19 lockdowns enforced in 2020, outlawing most economic activity and grossly violating the rights of innocents. I saw the following tweet from a claimed anarchist that I greatly respected:

Death is a pretty big curtailment of freedom, and projects that seek to increase freedom should try hard to avoid mass death as much as possible.

But I dunno, maybe your personal entitlement to Baskin Robbins is worth killing millions.

There are so many other mistakes involved there, like picking out only the least important casualty of the lockdowns and portraying the protests as about just that, and of course dismissing silently the fact that the lockdown itself killed people through poverty and such.

Covidianism