I have read up on it more than a "little." I happen to be in a very strong pro-life movement within the Catholic Church.
I have read studies that say that in cases where this pill fails to prevent fertilization, it prevents implantation. If it prevents implantation, that is destroying life.
The fact is that YOU will never know whether a woman prevented fertilization OR implantation. She probably will never know either. I think this is taking the argument to such extremes that it becomes....well, ridiculous.