[NotReady]

I think it's obvious why we believe Catholic doctrine was reformed by Luther and Calvin. That doesn't mean we think anyone has everything right or that Rome had everything wrong. I'm not a historian so I won't comment on the details of the development of the Reformation but I believe it started because Luther had serious problems with certain practices of the church. This lead to re-examination of doctrine and some significant differences between the Reformers and Rome became apparent.

But none of the Reformers have ever claimed perfection in doctrine. So different interpretations arose.

The Bible itself records differences between Christians. Paul warned about this in Corinthians. Acts tells of a major dispute between Paul and Peter. And Roman Catholics disagree among themselves all the time.