The bishop of Oregon can speak the truth, but he is not in a position to excommunicate her. That would have to be done by the bishop of the diocese she belongs to--whether San Francisco or Washington, D.C. Or by the Vatican. But the Vatican seldom interferes in local political matters.
From what I understand, the Bishop of San Francisco is a question mark. And the Bishop of DC seems determined not to act. Perhaps some of his fellow bishops can embarrass him into doing something.
I understand.