What makes a heretic? Part 2: John Piper and John Sanders

In open theism, describes John Sanders, 

  God has flexible strategies. Though the divine nature does not change, God reacts to contingencies, even adjusting his plans, if necessary, to take into account the decisions of his free creatures. God is endlessly resourceful and wise in working towards the fulfillment of his ultimate goals. Sometimes God unilaterally decides how to accomplish these goals but he usually elicits human cooperation such that it is both God and humanity who decide what the future shall be. God's plan is not a detailed script or blueprint, but a broad intention that allows for a variety of options regarding precisely how his goals may be reached.(1)

Also, 

  the omniscient God knows all that is logically possible to know. I call this "dynamic omniscience" in that God knows the past and present with exhaustive definite knowledge and knows the future as partly definite (closed) and party indefinite (open). God's knowledge of the future contains knowledge of what God has decided to bring about unilaterally (that which is definite), knowledge of possibilities (that which is indefinite) and those events that are determined to occur (e. g. an asteroid hitting a planet). Hence, the future is partly open or indefinite and partly closed or definite. God is not caught off-guard since he has foresight, anticipating what we will do. Also, it is not the case that just anything may happen, for God has acted in history to bring about events in order to achieve his unchanging purpose. Graciously, however, God invites us to collaborate with him to bring the open part of the future into being.(2)

In a chapter against open theism, John Piper--a very popular and respected Calvinist who was highly inspired by Jonathan Edwards--refers to a story of a young woman whose husband abandoned her. Why would God let me marry him if He knew he would abandon me? she wondered. In order to comfort her and help her keep her faith, her open theist pastor explained to her that God did not know that that was going to happen. 

Piper uses his own story as a response to that.

A woman from his own congregation heard the first story and wrote him a letter responding to it. She said that worse had happened to her with her husband and she was comforted by the fact that God did know what was going to happen and that "God intends this whole thing for my good. It's not just that everything will turn out all right in the end; it's that right now he is working his purpose out in my life, to move me to the next degree of glory."

For this reason, among many others, Piper concludes that open theism is "theologically ruinous, dishonoring to God, belittling to Christ, and pastorally hurtful."(3)

Most evangelicals agree with Piper on this. In 2004, John Sanders lost his tenure and was booted out of  Huntington College because he is an open theist and, worse, a popular one.(4)
This was after being kicked out of the Evangelical Theology Society a year earlier for the same reason.(5)

Does anyone know of a Calvinist that was fired from a University or kicked out of the ETS for being a Calvinist? I sure don't.
Why?

Back to Piper's story.
I suppose it would be better to tell the lady, "Not only did God know about the fact that your husband would abandon you, he caused him to"..........

Somehow, it is better to say that God causes evil than to say that God doesn't know the entirety of the definite future.
Why is that the case?
Why is it that saying the future is partly indefinite to God's knowledge is synonymous with denying Christianity?
And why is it not the same for believing that God is the cause of evil? 
Why isn't Calvinism considered "theologically ruinous, dishonoring to God, belittling to Christ, and pastorally hurtful"? (It definitely is to me)

I would like to add that Sanders wouldn't deny that God is "working his purpose out" in the lady's life. He would say that God adapted to what her husband did and altered his glorious plans for her accordingly.


Notes:
(1) Sanders, John. "An Introduction to Open Theism." Reformed Review (Online) 60, no. 2 (March 1, 2007), 35.
(2) Ibid., 35-36.
(3) See John Piper, "Grounds for Dismay: The Error and Injury of Open Theism," in Beyond the Bounds: Open Theism and the Undermining of Biblical Christianity, eds. John Piper, Justin Taylor, and Paul Kjoss Helseth (Wheaton: Crossway Books, 2003), 371-384.
(4) Stan Guthrie, "Open or Closed Case?" Christianity Today: http://www.christianitytoday.com/ct/2004/decemberweb-only/12-20-32.0.html
(5) Ted Olsen, "ETS Leadership Issues Recommendations on Kicking Out Open Theists." Christianity Today: http://www.christianitytoday.com/ct/2003/octoberweb-only/10-27-41.0.html