Mass is by divine institution not a mere fellowship like a casual banquet in your home, or the drunken agape gatherings in the early Church. It is the sacred divine worship of Almighty God, the Father, Son, and Holy Ghost, in the consecrated House of God, the church. This is in part why the priest sins giving scandal every time he breaks a rubric.
Few people know the priest must bow his head every time at the name of Jesus during every Mass or other sacred rite. To omit this is an objective sin that causes scandal, like any other liturgical abuse or irreverence.
St. Thomas Aquinas’ teaching has already been embraced and permitted to by followed by past Popes. He taught reasons that excuse attending Sunday Mass includes scandal at Mass.
Therefore, it necessarily follows, using basic syllogistic logic, apart from the debate whether or not the Novus Ordo doctrinally obscures the true nature of the Mass (the propitiatory sacrifice), that if the priest habitually omits bowing his head at the name of Our Savior (how would he not be aware of the rubric learning and using the missal?), among countless other potential liturgical abuses, since those give scandal, the Society of St. Pius X points out (the FSSP etc. de facto refuses to do this to preserve their TLM apostolate) this fact on its own creates a barrier to attending the Novus Ordo that releases the obligation. For those who dispute this IS the rubric, which the breaking of indeed gives scandal, that liturgical scandal is reason not to attend a Mass without sinning, I encourage you to email the SSPX and ask to chat on the phone about this with a priest. Happy Fall weather from Oklahoma.