I think the early posts in this thread has already answered the OP. I’ll just add something on #3. As stated earlier, individuals in the Church sometimes commit “personal sin.” That’s why we sometimes hear some scandals in the Church. But then again, even the apostles committed such “sin” themselves. As stated in the Scriptures, Judas betrayed Jesus, Peter denied Jesus three times, Thomas doubted if Jesus really rose from the dead and Paul used to be prosecutor of Christians. Now, did those mistakes brought about by human weaknesses affected the spread of the Church throughout the world? No. Did that affected the credibility of the Church? No. Did those mistakes put the Apostles as a whole fall into despair? No. Did that affected the credibility of the Apostles as a group? No. Did those mistakes affected their mission? No, in fact, in spite of those mistakes, they become even more greater as compared to before (except on Judas Escariot who hang himself on a tree; probably he thinks that he committed a great sin, too great that it cannot be forgiven).
So I think it is also important to ask, do those mistakes committed by the people in the Church destroyed the Church or caused it to cease from existing? No. Only proves that this is the True Church because the powers of hell NEVER succeeded against Her.
Church may be divine, but we have to remember that those who are in it are just humans, with human weaknesses that can sometimes make them fall into sin. It is true that the Church members have human sinfulness and weaknesses. But, the Church, led by the Holy Spirit unceasingly exhorts her sons “to purify and renew themselves (LG #7)”. And just like what Bishop Fulton Sheen (not sure if he’s “venerable” or a “blessed”) once said, it is not said (in the Scriptures or any Church teaching) that we (the Church members as a whole) will never be tempted. What was said is that we will be able to overcome.
