Adulterous Christians are living as if that commandment isn't in the Bible. And to argue this point to many who practice adultery in the church (even among the leadership), they explain their actions away. So in essence, to use your statement, the church IS celebrating an adulterous lifestyle. Whether we remove the adultery commandment from the Bible or not, the fact of the matter remains we, the Church, are living as if it doesn't exist.
We are all sinners. Not necessarily adulterers or homosexuals, but only homosexuals deny their sin IS a sin and celebrate it in the streets. You’ll have to show me evidence otherwise.