Is Bechirah A Good Thing

The Gemarah Sotah (36b) says באתה דיוקנו של אביו ונראת לו בחלון.  Yosef had a glimpse of Yaakov's face and that is what stopped him from sinning.  If Yosef had an external experience which stopped him from sinning why is he given credit for withstanding the test of Potiphar's wife?  

One approach of some seforim is to say this was not an external revelation of the face of Yaakov being conjured up before him but was a reflection of an internal resolve on the part of Yosef not to sin.  Yosef looked within himself and saw that he bears a resemblance to the holy face of Yaakov, etched on the כסא הכבוד and he realized it is not worth throwing it all away to do a sin.  That is the חלון that Chazal mention, a window can reflect that face of the one who looks into it.  Yosef saw a reflection of his potential face, of the face of kedusha that he will obtain if he refrains from sin.  When Yosef had this thought process, he received the fortitude to abstain from sin (from sefer הגיון לבי.)   

The Sfas Emes (5636) has a chiddush which he uses to explain this problem.  As an introduction, one school of thought (I think the common understand,) is that bechirah is a positive quality of man (as some understand לם אלוקים means,) a reflection of the Godliness within mankind.  Choice is what elevates mankind over animals who act purely based upon instinct.  Mankind is endowed with the girt of choice, one is given the ability to control their natural tendencies and choose a path of action.  The Sfas Emes here says the total opposite is the truth.  In the thought of the Sfas Emes, bechirah is an outgrowth of golus.  "עיקר הגלות הוא תוס' הבחירה כי אם לא הי' הבחירה כלל לאדם הי' ממש בן חורין"  In other words, naturally man should be like a malach, automatically programmed to do the desire of Hashem.  It is the sin of Adam that brings bechirah into the world and man is thrust into a life of choice, a life of distinguishing good from bad, of peeling away layers of falsehood to try to reach the truth.  The Sfas Emes says the test of Yosef was such that it was not humanly possible to overcome.  The only way Yosef was stopped from sinning was "רק ע"י רצון ולב אמת וצדק שיש להצדיק. זוכה שיקחו ממנו הבחירה שיצא מהנסיון. ופי' שיסייענו משמים." a removal of bechirah.  The removal of bechirah from Yosef is a harbinger of the geulah from the golus of Mitzraim and the geulah from all of the goliout which occurs when bitachon is removed.  The Sfas Emes (Bo 5638) says that was the message of bechirah being removed from Pharoah.  The message is that bechirah, the darkness of golus, is also under control of Hashem and can only go so far as Hashem allows it.  The Sfas Emes does not quote this Chazal in this piece but it fits in light of his approach.  Yosef did not have it within himself to withstand sin and indeed it was only through an external removal of his bechirah that he was able to avoid sin (see Sefer שערים אל הפנימיות Chapter 4.)  

See another approach in Likutay Moharan (#72 and volume 2 #150,) I'm not sure what he means.