In the first minute of this video (2009) you can see the extent of +Fellay's sacramental theology. ABL should have tested him before making him a bishop, or even a priest. With what he believes, he could not possibly object to the N.O. Mass. He must think the words of consecration are magic words. Listen carefully to the first minute. It is truly an embarrassment.
This video is divided in many 15 min. sections.
Actually, what +Fellay said is not new, I remember not long after Fr. Anthony Ward was ordained that he told a similar story that +Fellay tells in the opening minute of that video - that was back in 1972 or so. Fr. said he learned it from his seminary professor, which is probably the same story all the seminarians were taught back then.
The jist was, to err on the side of caution, validity was presumed.
To think that a priest, with the wrong intention (mad at his bishop), most likely the wrong form and matter can "consecrate all the bread in the bakery" or "all the wine in the cellar", outside of the Sacrifice of the Mass, is simply madness.
Leavened wheat bread is still valid matter, and so is any wine without added sugar or other additives. The valid form we all know, and the valid intention of doing what the Church does, theologians say, is very easy to have.
So yes, a priest who wanted to spite his bishop would be able to consecrate a whole bakery, or even a whole wine cellar (it would be a sacrilege), and if externally he followed the form, validity indeed would be presumed for obvious reasons (erring on the side of caution).