I agree with you, 1 is too many.
But check the actual study, these arent real numbers as the study itself states. This is just the rape count multiplied by expected fertility rate. Teh real numbers wouldnt be anywhere near this because 1) 10% of those numbers occur in states where they could legally get abortions 2) the other 90% could and probably did go out of state for abortions so the real number is likely a very small portion of the number stated.