Upvote:2
The confusion may arise from the way you've stated the view. A clearer version might be:
"If person P experienced circumstances C, she would freely choose to perform action A."
This doesn't mean that P must choose A, it means that P will freely choose A. If P were to freely choose not-A, then God would know something different from eternity, namely P will choose not-A, given C.
An example: if you offered your friend the opportunity to freely choose to stick his hand in a pot of boiling water for the fun of it, you "know" (really "assume", since you're not omniscient) that he would never do so. The Molinist view is similar, but stronger. Since God knows all things infallibly, he knows with absolute certainty what you would freely do in all possible circumstances, not just the extreme, boiling water contrivances.
An excellent (and short) book on this topic is The Only Wise God: The Compatibility of Divine Foreknowledge and Human Freedom by Dr. William Lane Craig.