How does the story make you feel? What did you imagine? What pictures did you have in your mind?
For me this story is neither sad nor pessimistic, even if there is a broken love affair at the end. The protagonist himself has no remorse either but is only glad to have escaped being blinded by his "adopted" peers! Thankfully for him, Nunez's "urge to merge" didn't quite convince him to follow through with his ghastly "rehabilitation." He asserts his individuality and wins back his liberty, once he manages to work his way out of that God-forsaken valley.
As with many other tales of journeys, this story is also figurative. (The road is life; the forks in the road, choices; the destination, one's goal.) Instead of submitting to the fate of being blinded for love (get the connection - "love is blind?"), Nunez resists conformity and flees the valley in the nick of time.
Once he has escaped, Nunez contemplates not the valley below but the beauty of nature in the lichen beside him and the stars twinking above. He can still see and appreciate "the big picture" instead of wallowing in self-pity. The tone at the end is one of wonder and gratitude, not that of pathos and regret.