"...then I would understand them to be excommunicated latae sententiae as well... "
Then why are they in our seminaries and working in collusion with the Maryknoll order? Why are their priests being granted faculties by American dioceses?
Doesn't this make the Maryknolls and these dioceses participants in their scism?
If you support the SSPX schism, yiou are not entitled to refer even to Maryknoll facilities as "our" seminaries unless you see them as commubnist seminaries and support that idea too.
Whatever may be true of the Maryknolls and the dioceses allegedly cooperating with the Chinese "Patriotic" Association, it does not let the execrable SSPX schism off the hook as schismatics led by excommunicates. Moral relativism is not applicable against the judgments of the Holy Father.