The question is, what is the probability that a person picked at random from the human population, would be born during a technological era. We can work this out. Then, what is the probability that the part of the technological era they were born in was the first 100 years. This is easier to work out, it's 100/L_years(technological_era) but, unfortunately that's also the probability they are born in the second 100 years of a technological era of the same length, the third 100, the last 100 etc. so I don't think it gives us any predictive power?
That just leads you down the road of discarding probabilities. Since something either happens or doesn't happen, the probability is either 100% for the things that will happen or 0% for those that do not. This is not a helpful position to take, although it is technically correct, in some not very useful sense.
Humans are good at dealing in counterfactuals. 'What would have happened if I hadn't missed the bus?' is a useful question to ask, even if you did miss the bus. What would I be like if I hadn't gone to university/had taken that job/never killed my parents? Obviously the 'I' in those questions cannot be you, exactly, since you did or didn't do those things. But it's still a useful concept or thought experiment, and can give us valuable insights.
The commenter is using 'I' in that counterfactual sense. And certainly, I understood what they meant by it, so they were successful in communicating (at least, to me) which is what matters with language.
