Either make the tree good, and his fruit good; or else make the tree corrupt, and his fruit corrupt: for the tree is known by his fruit. O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh. A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things.
That may be your point, but the basic conclusion is wrong. NOBODY bases their faith upon Martin Luther. Even the denomination Lutheranism came about after he was gone. Some keep forgetting that the seeds of the Reformation began before he was even born, happened in other countries besides Germany, had many others involved in it and continued long after Luther died. The reforms that HAD to happen within the Catholic church, did so because Almighty God was behind it. The Catholic church was NOT holy nor apostolic for a long time. So, if you want to cast out those categorized as "Protestants" (which is a catch-all for non-Catholic Christians) because of what a part of what one man did or thought, you have FAR worse examples right there in that imagined unbroken line of Popes. Be careful with what you use to judge others.