Why was it not written "I, Eliezer Yudkowsky, should choose to submit to 50 years of torture in place of a googolplex people getting dust specks in their eyes"?

Because then it's clearly not the same argument anymore, and would appeal only to people who ascribe to even a narrower form of incredibly altruistic utilitarianism, who I personally suspect don't even exist statistically speaking. Say the person chosen for torture is random, then it would make a bit more sense, but would essentially be the same argument given the ridiculously high numbers involved.