“Doctrine” entered English in the  late 14 century from Old French “doctrine” and directly from Latin “doctrina” - "teaching, body of teachings, learning".

It is comprised of the "the act of teaching" and "the knowledge imparted by teaching", and “doctrina” is often used in the New Testament, especially in the Pastoral Epistles, in the Vulgate.

In general, doctrine is all Church teaching in matters of faith and morals. Dogma is more narrowly defined as that part of doctrine which has been divinely revealed and which the Church has formally defined and declared to be believed as revealed.

The revelation exposited at the Council in 325 AD did not come into existence then, it was part of the revelation which ended with the death of the last Apostle.

Compassion has not a whit to do with it.