Here is a September 22, 2015 letter from my bishop on the limits of participation in the life of the Church by those who openly reject the Catholic teaching or way of life and worship.
Principles to Aid in Preserving and Protecting the Catholic Faith in the Midst of an Increasingly Secular Culture
I. The Church will continue to cherish and welcome her members and invite them to participate in her life to the degree that their personal situation permits them honestly to do so. Catholics must be in a marriage recognized as valid by the Church to receive Holy Communion or the other Sacraments. Non-Catholics and any Catholic who publicly rejects Church teaching or discipline, either by public statements or by joining or supporting organizations which do so, are not to receive the Sacraments. They are asked to be honest to themselves and to the Church community.
II. Parishes and other institutions of the Diocese should allow use of facilities only to persons and organizations which agree with the teachings of the Roman Catholic Church and its canonical legislation or, at least, no oppose them.
III. Catholics, especially ministers and others who represent the Church, should not participate in or be present at public religious events or events intended to endorse or support those who reject or ignore Church teaching and Canon Law.
Further Reflections
1. These principles apply to the parishes, institutions and programs of the Diocese. Pastors and others who lead in the Church should explain these matters in appropriate ways, privately when this is possible.
2. Please recall that the requirement of canonical form does not simply flow from baptism but rather from membership in the Catholic Church. While marriage involving even one Catholic is required to observe canonical form, that same requirement is not imposed in a marriage of a non-Catholic bride and groom. Even if both are baptized, they can validly marry as long as both are free to marry. Marriage between non-baptized men and women who are free to marry is valid. In all cases proper intent to marry is required.
3. If there is a question about any of these matters, kindly consult appropriate Church law or the Office of the Vicar General, the Metropolitan Marriage Tribunal or the Pastors' Administrative Manual of the Diocese.