The vast majority of Catholics are told must attend the NO under pain of mortal sin(no NO clergyman will tell you that you can stay at home as long as there's no Latin mass nearby). So yes, the attendance of the new mass is binding under pain of sin.
Novus ordo catholics are told this by their bishops/priests, not rome. None of the V2 popes, nor any Vatican official has ever declared this. In fact, as I said previously, Benedict XVI said in his "motu" that Quo Primum is still in force and that all priests have a legal right to say the True Mass. This is confirmation, directly from the pope/rome, that anyone can attend the latin mass and they do not have to attend the novus ordo.
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QP does not forbid the pope to revise the missal, popes have done it many time before
Agree but no pope since John XXIII in 1962 has revised, or attempted to revise, QP. John Paul II's commission to study the matter, which led to the indult mass in the early 80s, shows that Paul VI's novus ordo liturgy/law was not a revision but a new liturgy/law.
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Popes can of course violate canon law, but not when they're making laws. New laws override old laws.
New laws can override old laws, they also cannot. It depends what they say. We know for a FACT that Paul VI's new liturgy/law in 1969 did not override or revise QP because of Benedict's "motu". He confirmed this in 2007 when he said that QP was "not abrogated" and that the True Mass "was always allowed".
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Further, QP orders that ALL latin rite catholics ONLY say/attend the True Mass and they aren't allowed to use/attend any other missal. Paul VI's liturgy/law could've revised this part, in order to allow a new/2nd missal. This was within Paul VI's authority to do so...but he did not. Therefore QP's command is still in force and even though the new mass legally exists, those who say/use it commit a grave sin by using an illicit missal. The missal is legal, but to use it is illegal. Ah, what a diabolically clever situation the devil hath created! But the legalities are clear as day since the "motu". We can thank Benedict for that (and not much else).