This is nothing new. I am pretty sure this has always been the society's position. What +Tissier says is found in this sentence of his - "We cannot, of course, accept this new sabotaged rite of ordination which poses doubts about the validity of many ordinations according to the new rite". He also says that it is not catholic. And, that is true. But, he is not saying anything different than what +Williamson says.
The cogency and intellectual soundness of Bishop Tissier de Mallerais is well-established.
As Bishop W has said in the not-too-distant past, the engine purrs like a kitten but there is something amiss with the rest of the drive train such that the power does not get to the wheels.
The rite leaves open the possibility of invalidity. But, it is also possibly valid. And, this ambiguity is not catholic. So, the rite is not catholic.
So how about talking about this vague possibility of invalidity, or about this non-Catholic ambiguity? Here is where the purring engine's power doesn't make it to where "the rubber meets the road."
If, for example, vagueness and ambiguity in the faith is deplorable and unacceptable, how can a properly functioning bishop have no outspoken opposition to schmoozing with the heretics and apostates of Vatican II ideology and conformity?
However, seeing this clear-minded perception regarding the incomparable value to Holy Mother Church of the traditional form and rite of priestly ordination, it is most praiseworthy that +dM has with fortitude and extreme courage put his intellect into full capacity to the effect of making this TIMELY and POWERFUL sermon on this monumental occasion.
P.S. I highly doubt that DICI or sspx.org will touch this text of +dM with a 10-foot pole, but instead,
they will hope it fades into the renown Memory Hole of 1984..