Look at the difference in perspective between Msgr. Vigano here, and another famous lettre from the FSSPX:
Msgr. Vigano: Roman modernists intend to destroy the Church -
"It is evident that this relentless action of war against traditional Catholics includes a strategy and a tactic, and that it corresponds to a plan devised for decades to destroy the Church of Christ and replace it with its ecuмenical, globalist, and apostate counterfeit. It would be foolish to think that they act without a purpose and without organizing themselves.
Bergoglio’s election in the conclave of 2013 was also planned: let’s not forget the emails between John Podesta and Hillary Clinton about the need to promote a “springtime of the Church” in which a progressive pope modifies its doctrine and morals by enslaving them to nєω ωσrℓ∂ σr∂єr ideology.
Action against Benedict XVI was planned to push him to resign. The subversive work of the innovators at the Council was planned. The action of progressives loyal to Bergoglio was planned in the synods, in the meetings of the curial dicasteries, in the consistories. On the other hand, behind the enemies of Christ and the Church, Satan always hides with his plots, his deceptions, his lies."
FSSP (Abbe Simoulin): The Roman modernists do NOT wish to destroy the Church -
"That being said, can we really consider this authority as working for the destruction of the Faith? It would seem more accurate to call it an authority that does not profess the Faith, or does not confess it in its integrity, and that professes notions that are dangerous or even against the Faith. For there is a distinction to be made between an intention to destroy the Faith
and an effect that was not directly wished for. It is clear that this loss of the Faith is a consequence of the conciliar doctrine that has been professed for the past 50 years, but can we say that this was and still is the intention of its promoters? If such were the case, these authorities would no longer have the Faith and would no longer be formally Catholic, and to believe this would be implicitly sedevacantist."
https://sspx.org/en/news-events/news/avoiding-false-spirit-resistance-3764 No wonder there is no collaboration between Msgr. Vigano and the FSSPX: The former attributes evil intentions (supported by volumes of external evidence), while the latter believes the damage is incidental, and the modernists want to encourage Tradition. Who can forget Msgr. Fellay telling the Australian faithful that Rome's offer of an agreement is not a trap, and "they want to do good to us?"