Besides, the Church aknowledges fully with the idea that it was a suicide.
In Roman Catholic mass it is often said of Jesus that he is "Priest, Victim and Altar". If he is priest, then he is the killer, the sacrificer.
They simply are afraid of following their own ideas through the end and prefer to name a "suicide- that-brings-life to others" a "sacrifice", because they not know at all what the hell a sacrifice is, and so the whole thing gets conveniently hidden.