Today, the purpose of the homily:
29. It is the task of the homily and of catechesis to set forth the meaning of the liturgical texts,[Sacrosanctum Concilium, n. 35, 52; Inter Oecumenici 54; cf. POPE JOHN PAUL II, Apost. Exhortation Catechesi tradendae, 16; GIRM 65] illuminating with precision the Church’s understanding regarding the members of particular Churches or ecclesial communities separated from full communion with the Catholic Church and those of Jewish communities, as well as adherents of other religions – and likewise, her understanding of the dignity and equality of all men.[Unitatis redintegratio; Nostra aetate] Similarly, it is the task of catechists or of the homilist to transmit that right interpretation of the texts that excludes any prejudice or unjust discrimination on the basis of persons, gender, social condition, race or other criteria, which has no foundation at all in the texts of the Sacred Liturgy. Although considerations such as these may sometimes help one in choosing among various translations of a certain expression, they are not to be considered reasons for altering either a biblical text or a liturgical text that has been duly promulgated.
This is probably one of the most unsatisfactory sections in the whole document.
On one hand, it is laudable to suggest that difficult, dense, or deep aspects of the liturgy can and should be broken open in the homily.
On the other, it exhibits a callousness on the part of the CDWDS, not to mention a lack of depth in the understanding of liturgy. People don’t ordinarily pause when insult is delivered and wait for the explanation of the clergy. Such moments within the liturgy are a distraction and need to be expunged. The liturgy is far too important to be bogged down by a continual apologetics for textual missteps, especially the ones that have no grounding in Scripture.
Catholic Sensibility 
Another rationalization posing as a reason.