Denying BOD is a mortal sin. I proved that without a doubt.
Being flippant about Sacramental validity is also a serious matter.
Utter foolishness! I doubt that you have even read the seminal literature on the subject,
Bread of Life,
Gate of Heaven,
The Loyolas and the Cabots,
The Point,
et cetera. My experience is that those who bash Fr. Feeney have not even investigated the subject, which is, at most, intellectual dishonesty. Fr. Feeney was only defending the Apostolic Dogma that the Catholic Church is necessary for salvation, a dogma which every Catholic must affirm. I told Fr. Cekada over thirty years ago, "The sacraments are necessary for salvation; BOD is not a sacrament, and it does not save, however one might conjure up in his imagination its efficacy."