My flashlights will not work if the batteries are reversed. Not one of them.
That's fine. However, you extrapolated from this bit of information that
no flashlight will work with the batteries reversed, and even claimed to have asked electrical engineers why this was so, but could not get an answer.
And yet, even though I was apparently delusional, I could get it to work. Even showed you a video of it.
It's the same thing with this issue; apparently because birth control works in many cases, you have extrapolated that only people who want to have children, or are sex crazed, or don't use birth control at all, get pregnant. However, there are plenty of people who use birth control and get pregnant every year.
Just because you extrapolate does not mean that you are correct. In many cases, you are wrong.
BTW, since you wanted more hard data, below is a clip of a table
from this article which shows that even using the pill (one of the most effective birth control methods) about 13% of women experience birth control failures during the first two years. Is that specific enough?