The state doesn't track who is cheating, so all they can do to protect kids is to assume everyone is equally likely to cheat. If you think it is better they tracked your sex life to ensure they didn't punish the wrong people then you have very different values than most.
It doesn't have to be active sex life tracking, there are other ways. When cheater are punished, it will make others less likely to cheat. Win win for everyone.
