I think he has more weight than you do and I do not think he violates Vatican I, because no good Catholic ever would take a Dogma out of context. Concerning this particular topic, I think people are more focused on being right and not on being holy.
St. Alphonsus lived from 1696 - 1787.
The First Vatican Council 1868 - 1870
St. Alphonsus was clearly teaching his opinion of the decrees of Trent - and in the process even contradicted himself as we see one time he says only heretics say no sacrament is necessary and another time he says salvation can be had without the sacrament. This is fact and only fools who've blinded themselves will refuse to admit it.
His teachings were clearly trying to expand on what Trent actually said, but certainly anyone can see that some 100 years after the saint's death, V1 infallibly put an end to the practice of "interpreting" dogma, and from that time on, all are bound to maintain the exact meaning which has once been declared by holy mother church - period.
Again, if St. Alphonsus were to have been alive at the time of V1 and knew that the council infallibly declared that dogmas are to be understood "as declared", there is no way he would have done what BODers here continue to do - namely, twist the meaning of the infallible teachings to suit themselves - even after knowing that V1 binds us to understand dogma as they are declared.
From V1 on, no one is permitted to interpret any dogma for any reason. When Trent says the sacraments are a necessity unto salvation and that the sacrament of baptism is not optional - no one is permitted to add: "except in case of necessity" - or the actual sacrament can be replaced by the desire for the sacrament.
I believe everyone on this site is trying his best to deal with an unprecedented crisis and apostasy, and I think there needs to be a little more mercy and understanding and a lot less condemnation.
Perhaps the tone of some posts sound condemning, but when constantly dealing with outright dishonest opponents as most of the BODer participants here are, mercy and understanding will be in short supply.
The challenge I offered 3 months ago was, IMO, the best way to wake up the avid BODers - so they could see for themselves that it is impossible for them to defend the sacraments, because if they were honest, they would either admit, at least to themselves that they do not believe the sacraments are a necessity at all, as such, that they cannot defend that which they despise.
I hoped it was a means to show themselves they are in deep error since certainly they know it is a strictly Catholic thing to defend the necessity of the sacraments - - so if you cannot get yourself to do that, then you should be able to discover that there is a major malfunction within your own belief and thinking.
But, it hasn't worked, not yet any way.