That is not the Roman Catholic Church. It is the body of Christ, the church. All who proclaim Jesus as their savior are part of the “body of Christ” the church just as they were during the time of the Apostles.
That may be your supertition but I don't see anything in the scripture where heresies such as Protestantism were tolerated. Either one of the multiple Protestant denominations is the True Church, or the Catholic Church is, together with the apostolic Churches that believe what we do. You cannot have the body of Christ without agreement between the members on the fundamentals of faith, adnd we don't have such agreement with the Protestants.