Must, Or Even Ought the Homily Reference the Lectionary Readings Of the Day?

According to this document of the USCCB the practice is "warranted":

 In addition, this very integration of the homily into the texture of the liturgy warrants the use of the Lectionary readings as the basis for the homily.

And to support this contention, the Code of Canon Law is cited, this passage specifically....:

Can. 767 §1. Among the forms of preaching, the homily, which is part of the liturgy itself and is reserved to a priest or deacon, is preeminent; in the homily the mysteries of faith and the norms of Christian life are to be explained from the sacred text during the course of the liturgical year. 

...which says nothing of the sort.