What you must understand is that infallibility is not something that man claims for himself. It is given by the Creator.
Some truths are infallible because they are declared to be truth by the teaching Magisterium of the Church.
Other truths are infallible because they are revealed to us by reason. Abortion is one of those truths.
Reason tells us that man cannot destroy innocent life. We all understand that there are situations when there is a threat to the life of the mother, but that does not make the unborn child guilty.
We had this case in our marriage. We were told that my son would kill my wife if we did not terminate the pregnancy. There was no way that we could terminate this pregnancy, because this child was not guilty of the danger in which his mother found herself. The danger was due to circumstances beyond the control or the wish of our son.
Reason told us that we could not justifiably kill our son, because he was not a threat. The threat was created by natural causes. Even though we had two other children, this child had a right to enter the world or die a natural death trying But he had the right to be given an opportunity to develop naturally, because he had done nothing to abdicate that right or have it taken away from him.
Today, I do not regret our choice. He is a wonderful young man.
As you can see, reason has its on infallibility and those who speak using reason are speaking infallibly. This is not too much power. This is simply truth.
Truth is not about power. It is about things being the way they are, not the way we would like them to be.
Fraternally,
JR