This is a most excellent question and one that, in the present age, all Catholics should stop and ask themselves. In the wake of abuse scandals, against a world that sees us as backwards and bigoted, and facing daunting challenges in evangelization, all the faithful should have a ready answer for why they remain when remaining seems, in the eyes of the world, so foolish.
I have many and varied answers for why I remain Catholic: because of the beauty of the liturgy; because the Church, despite all the flaws of her members, remains a force for good in the world; because I was raised Catholic and finding a new spiritual home sounds like way too much work. But the most foundational reason is that because the teachings and worldview presented by the Church constitute the most consistent and coherent set of propositions I’ve encountered — coherent in that it matches my own experience and observations about the nature of reality, and consistent in that it is systematic and non-contradictory. (Indeed, the systematic nature of the faith was one of the things that contributed to my spiritual awakening in college and beyond.)
What’s more, this worldview helps me to see beyond my own myopic vision and to overcome my own self-interested biases. This is part of what is meant when we describe the Church as a hospital for sinners — it strips away our excuses and denials and distorted passions, allowing the root of the problem to be diagnosed, treated, and cured by the Master Physician.
Of course, all of this would be as nothing if it weren’t for faith, since it is faith that allows us to see the coherence and consistency of Catholicism. Our faith is not scientific; it does not rest on demonstrable proofs or repeatable experiments. I agree with Chesterton that “original sin… is the only part of Christian theology which can really be proved.”
And that is the paradox: faith doesn’t make sense from this side. It’s only by crossing over — by taking the proverbial “leap of faith” — that we get the proper perspective and can begin to retrain ourselves to see the world, ourselves, and God as they really are.
And that’s why I remain Catholic: I have crossed the chasm and become, to paraphrase the Apostle, a fool for Christ, even as I follow him imperfectly in starts, reversals, and blind reaching. Yet it is in the striving to achieve holiness that the world takes on meaning and hope is made manifest — not due to our own efforts, but because in the reaching we find God, in his infinite mercy, reaching out to us.
Where else could I remain?