A friend of mine reminds me every time I need to vent about the insane things that go on around the church or with people - "Where there are no oxen, the manger is clean (Proverbs 14:4)." Christianity is a messy enterprise. People who come into the church are hurting, broken, damaged, angry ... so many things. And working with them to help them find healing and restoration is messy. But once you become a Christian, that doesn't mean that all of the stuff of life ceases to affect you. In fact, it may get worse. Whether it gets worse or not (which is an entirely different area of debate), the fact remains that LIFE still happens, and LIFE brings with it pain, and sorrow, and disappointment, and frustration .... All this is a result of us living in a fallen world. When Adam and Eve ate of the fruit and disobeyed God and were cast out of the garden, it didn't just affect humanity. Farming and cultivation became more difficult, reproduction became more difficult, death and disease entered into the world, and we all deal with these prices of sin today.
So while we may be redeemed by Christ once we are saved, we still live and exist in a fallen world. We aren't immune from the symptoms of the disease, so when life strikes, it can strike the Church as well. Jesus said that the rain falls on the righteous and the unrighteous. Not every hardship is an assault from Satan or a trial from God - sometimes it's just life.