"The Church is filled with sinners and hypocrites and so can safely be ignored." - Typical Anti-Catholic Statement.
"The Church is filled with sinners and hypocrites and to claim this is to claim what the Church herself teaches." - The Catholic Church
"The Church is not justified when her children do not sin, but when they do." - G. K. Chesterton
When asked why he became Catholic, Chesterton answered, "To get rid of my sins."
When an opponent quite rightly chastises us for our failings (see the combox here) - from greed to hypocrisy to sex abuse to cowardice, etc. - the reply can only be, "You despise as vices the same things the Catholic Church has always insisted were vices; you admire as virtues the same things the Catholic Church has always insisted were virtues. The truth of what the Body of Christ teaches is not determined by the moral uprightness of the sinners who serve as its teachers; the truth is greater than man, and the teaching is not of man, but of God. When we sin we witness for our need of a savior; when we are holy, we witness for His grace working in us."