Your argument is full of holes. First, leftists somewhat rightly claim that the Constitution is neither religious nor Christian. Leftists also claim that many founding fathers were either irreligious or atheists. Furthermore, few godly, God-honoring Christians had anything to do with fashioning government rules and no God-honoring Christian is on record supporting the abuses of slavery.
You say Christians supported gay persecution but you offer no proof other than your flimsy claim that gays have been offended by Christians believing and preaching God's word. Tough toast. Gays have their freedom to believe and preach their views and so do Christians.