Are distinctions like these just legalism?

Ectopic pregnancy. In an ectopic pregnancy, where conception occurs outside the uterus, the fetus cannot survive. The other procedure you mention removes a viable fetus. This is no hair-splitting: an innocent human being is deliberately killed. The end never justifies the means, even if the mother will die. God may take innocent life, having the right to; we do not.

Annulment. An annulment is the process determining that a valid marriage never took place, leaving the persons free to marry. Without such proof a marriage is ordinarily presumed valid. One cannot be married to two people, and civil divorce cannot dissolve a valid marriage.

The Divine Mercy Chaplet. Praying it is in no way opposed to asking God's mercy in other ways and circumstances.

These are not legalism; they are reasonable once understood. We must beware of false dichotomies and simplistic conclusions about the Church. Through the Church we meet Jesus in the only way anyone can: with humble gratitude.