We all have faults and failings, and that is why Jesus came and died on the Cross for us. No one is perfect, just forgiven. The Scripture says, "There is forgiveness with Thee, that Thou may be feared." and, "He who has been forgiven much, love much".
It is just that people like Jim and Tammy Bakker, because they were prominent in the public arena, their faults stood out a lot more than those of the rest of us. We can keep our faults and shortcomings hidden from others, and can make a good pretense of being holy and righteous; but God sees all, and, in many cases those who point the finger at Jim and Tammy, have three fingers pointing back at themselves. Others may not see it, but God does.
If people were and are saved through their imperfect ministry, then they have achieved better results than most of their critics. But, in that day of judgment when the secrets of people's hearts are made manifest, then we will see who were the ones who were really right with God and those who weren't.