Non-Catholic Christians Are a Part of the Body of Christ

Vatican II teaches that Jews who reject the gospel are not to be considered rejected by God. Nostra Atate says, although the church is the new people of God, the Jews should not be presented as rejected or accursed by God. The Protestants and Sismatics who reject the papacy and other dogmas are in the body of Christ. So you can't say Protestant baptism is invalid just because it's not Catholic.