Cynicism is subscribing to the belief that nothing will go as planned and that nothing works out for the best. For 1984, it really does depend on who you ask!
Primarily, the reader identifies with Winston, the conflicted protagonist whose failed attempts to join an uprising lead to his torture and his reintegration with society. For most readers, this ending is not satisfying. The torture is expected, and if all Winston has to do is endure torture or die from it, then he becomes a martyr, a hero. Unfortunately, Room 101 is not the end for Winston. He admits that 2+2=5 and blindly accepts all other misinformation from the Inner Party in exchange for his life. All that is left is for him to spend his days at the Chestnut Tree Cafe without a care in the world.
What the reader may dislike the most is that he, himself, is essentially Winston. We all are. Few people in real life become the martyr or the hero or the successful leader of a much-needed uprising. Winston's failure is every man's failure, and thus is the birth of the cynicism.