Once again you are confusing the day after pill with standard oral contraceptives. Ovolation is surpressed ergo no fertilization. Hypothetically, if ovulation was not surpressed your aborticant scenario may be true. But it is rare and little more than a weak rationalization against OC.
As this thread demonstrates there is no shortage of exaggeration and misinformation regarding the pill.
I've confused exactly nothing. Ovulation is NOT ALWAYS surpressed, although, I agree it is a main goal.
How common this failure is, I have no idea. I did, however, experience it personally, for about 6 months on one particular pill.
I suspect it is more common than you wish to believe.