Regardless, any Bishop who sees the SSPX as a danger to the faith and who singles them out in spite of inviting ecumenical worship with protestants (not necessarily an issue in itself) is way off course.
Anyone who has gone to the SSPX for their entire life also can’t be excommunicated for adhering to a schism.
What Bishop Bruskewitz was asking in that matter was: “Why are you attending the SSPX and being disobedient to my directives in the diocese”?
Some answers to that might be:
“Your Novus Ordo Masses are liberalized and a danger to the Faith”.
or
“Vatican II taught false doctrine and I can’t be taught by a Vatican II priest”.
There are other similar views - including “The Novus Ordo is invalid”.
But how does the bishop react to that? Agree with them?
I think he said, by his action: “The Novus Ordo Masses here are good and the priests here are good.” He also supported a very strong center for traditional Latin Masses with the FSSP seminary in Lincoln.
The argument that “he invites Protestants to worship but opposes the SSPX” really doesn’t work as I see it. It is saying that his ecumenical gestures should be extended to the SSPX. But that’s just applying liberalism equally to the SSPX. In the old days, if priests disobeyed the bishop or the Pope they’d be excommunicated just for that alone.
So, for the SSPX to appeal to liberalism and fair-play seems weak. Accept the ruling and don’t complain. If you want to fight it, then take it to Canon Law. That’s fine.
We all like fair-play. “He allows Protestants privileges but not us.” But very often it doesn’t matter what everybody else is doing, it only matters what we do.
He who has been given much, much will be expected.
St. Athanasius was exiled from the Church by the heretics in charge at the time. But he accepted it.