Yet according to official (subject to what "official" means) RC teaching, assent to encyclicals is required, and in general to non-infallible papal teaching addressed to the church. Which is both the strength (if unity at any cost is the goal) and the weakness of the RC basis for assurance of Truth and obedience to it.
For rather than the validity of what is taught being subject to by examination in the light of the authoritative basis for it, which Caths criticize evangelicals for doing, while dissident "true RCs do the same (the difference being the supreme deterministic authoritative basis for evangelicals is wholly inspired Scripture), much historical papal teaching is that "the one duty of the multitude is to allow themselves to be led, and, like a docile flock, to follow the Pastors ." - VEHEMENTER NOS, an Encyclical of Pope Pius X promulgated on February 11, 1906.
All encyclicals, before this pope, were written so that he could say "We teach," very much like Peter himself speaking for all the Apostles. Francis did not include the teaching authority in Amoris. He had his people send out questionnaires and he conferred with a few like-minded bishops. That is contrary to how the Magisterium works.
An encyclical is meant to present to the Catholic Church the teaching of all the bishops. In this one he picked a few friends and is trying to pawn it off as "The Official Teaching of the Roman Catholic Church."
Many people know better than that and that is why he is getting the blowback and deservedly so.