Why does Winston believe that chastity is a symbol of political orthodoxy in 1984?

In Book 2, Chapter 3, Winston decides that there is a “direct, intimate connection between chastity and political orthodoxy.” He asks how the fear, hatred, and absurd willingness to believe untruths could be kept at a frantic pitch unless the Party restricted or eliminated the powerful basic instinct of sexual pleasure. The Party thinks sex is dangerous because, if people were allowed to have it, they would not be tense and repressed enough to want to hate the “enemy.” Sexual tension leads to more enthusiastic demonstrations of Party loyalty. Unable to release pent-up emotions through personal relationships, people channel their frustration and longing toward the ideals of good and evil the Party presents them. Political orthodoxy prevents people from connecting on an intimate level, and the group dynamic of fear and hatred is fueled by this basic lack of human connection.