This a good example of why the history of Christianity is division and subdivision, which obviously is continuing. The guys who run the Catholic Church (and they are all guys) decided to make abortion some sort of litmus test, which is absurd. There are all sorts of beliefs, theories, and conclusions on the subject, among both individuals and religious organizations, both Christian and not. And abortion is not the only subject on which opinions differ widely.
There is always a problem when one gets involved in an authoritarian organization. A small group of hand-picked individuals gets to make decisions for everyone. I have never regretted leaving the RC Church, which I did years before Roe v. Wade was decided. It is important to note here, before any posters go crazy that I have some obligation to continue as an RC, that I did not choose the RC Church, my parents enrolled me from birth. A close friend of mine switched not long ago from RC to Unitarian, and she is so happy she did.
As Biden has held a public office twice, and could again, I think that he is smart enough to know that a public official must exercise his/her duties on behalf of all the people, not just those of his/her own faith, even if the RCs want to reel him in.