Isn't Open and Affirming simply a reaction to pressure from militant gays and lesbians and their families to endorse a homosexual "lifestyle"?

No. Open and Affirming is a response to the good news of Jesus Christ. It is based on careful and prayerful study of the Scriptures and of the Christian calling to love the Lord your God with all your heart, soul, and mind and to love your neighbor as yourself (Matt. 22:34-39). Open and Affirming is about our responsibility as Christians to "welcome one another as Christ has welcomed you, for the glory of God" (Romans 15:7). As for "lifestyles," the Open and Affirming Statement endorses only a Christian "lifestyle" for everyone, whatever one's sexual orientation may be. It encourages fidelity and mutual respect. It is based on the belief that the blessing of God is intended for all who keep God's covenant and obey the commandment of Jesus to love one another (John 15:7).