Long answer: I believe the answer lies in a fundamental differences between Catholics and Protestants. Until the Reformation all of the tendencies that eventually crystallized out as separate Protestant denominations existed in vibrant tension WITHIN the Catholic Church. Protestantism began by splitting off the maternal Catholic trunk, and Protestants have continued to solve disputes by forming new branches or denominations. On the other hand, despite the fortress mentality and resistance to change of the Roman curia and hierarchical magisterium, the Catholic Church has continued to welcome an almost infinite variety under its vast rainbow umbrella. Pluralism is not only not alien to the Church; pluralism is pro-foundly catholic! This is as much the Church of Johm Paull II, Opus Dei, and Mother Angelica as it is the church of Hans Kueng, Teilhard de Chardin, Elisabeth Schussler-Fiorenza, Karl Rahner, Arlene Swidler, Raimon Panikkar, Rosemary Ruether, Charles Curran, Andrew Greeley, Leonard Swidler, and me--Ingrid Shafer :-). Plus everyone in between who considers her/himself Catholic!
Catholics have a long-standing habit of remaining within the Church as loyal dissenters, something Protestants don't understand because the Reformation began a tradition of denominational splitting that preserves in-group uniformity at the expense of malleable (if ambivalent and inconsistent) inclusivity. The Protestant conscience asks, "If you don't like the rules, why don't you just get out?" The Catholic imagination answers, "I like being Catholic, I like the pictures, I like the stories; there's a lot more to the Church than rules!" This Catholic attitude cuts across the entire spectrum of believers from the most conservative to the most liberal and may hence be the most fundamental marker for the Catholic sensibility. It tends to keep liberal Catholics Catholic, no matter how disgusted they are with what they consider official rigidity; it also keeps conservative Catholics Catholic, no matter how appalled they are at the changes that have already taken place. For us Catholic cats the Church is our alley!
Hence, the Catholic position is open to continuous re-envisioning and re-imagining in light of historic developments and grassroots experience. For most of Church history, this continuous if often imperceptible hermeneutical shifting has tended in two divergent directions. As identified with the official position of the respective magisterium of a particular period it has lagged slightly behind actual socio-economic conditions and scientific discoveries. Occasionally, it has also anticipated such changes as a push from below. This malleability permitted Karl Rahner and others to speak of the church as ecclesia semper reformanda--the eternally self- reforming church. It also lies at the core of Pope John XXIII's insistence that the Church must adapt to and learn from the world. Hence, as Richard McBrien notes, the conciliar document _Gaudium et Spes_ is also known as _Pastoral Constitution on the CHURCH IN THE MODERN WORLD_ (emphasis mine)--IN the world, not AND the world (or ABOVE the world)! Church and world in a relationship of mutual interpenetration and interdependence. The Pope approved of an address to the Council in which Cardinal Suenens said "We must therefore recognize and understand the world in which we live, its expectations, its longings, and its often dramatic characteristics" (_Catholicism_, 1981, p. 85).
And so I say, THIS is the church I love; it is MY church; I am part of this process, and NO ONE can tell me to get out!
Pax et Bonum,