At least some of them are, anyhow. More so, in my opinion, than most of SSPX, in fact.
183 of 189 bishops defiantly disobeyed Rome on a matter concerning a central tenet of Faith and Morals. That is schism, and it represents 97% of Amercan bishops.
It IS possible that USCCB president Wilton Gregory and Cardinal McCarrick withheld Ratzinger's letter from the USCCB prior to the June USCCB meeting.
That is very doubtful, but if it is the case, the USCCB should have an emergency meeting to reevatuate their schismatic position and impeach Wilton Gregory.
And Rome should send McCarrick to Siberia.