I don’t know that he spoke of excommunicating Biden. He was the top administrator of the USCCB but not a bishop and not a member with a vote.

A majority of the bishops on the conference voted to move things along toward denying Biden communion, but they have not formally explored excommunicating him, even though a couple bishops have talked about that, including the senior Bishop of the conference who is the president of the USCCB.

I think some people are conflating the offices of general secretary and president or perhaps conflating denial of communion with excommunication.