Suppose an unbeliever were unusually prideful. In evangelizing the individual, would you explain the sinfulness of pride, get the individual to renounce it, and then explain the gospel and the way of salvation? Christianity is not cleaning up our act enough that we can come to God for forgiveness. However, broad evangelicalism tends to treat homosexuality that way.
I fully recognize that repentance is a necessary part of salvation. But, who on this board can claim to have recognized, repented of, and turned from every form of sin upon conversion? The root sin that needs to be addressed is the sin of rejecting and suppressing the knowledge of God - believing that we can live acceptable lives apart from God. Repentance from this sin - beginning to live a life seeking a deeper knowledge of God and seeking to live a life in conformity to God's Lordship - seems to me to be the a key first step in becoming a Christian.
What does it mean to live a life in conformity to God's Lordship? I doubt anyone here can fully answer that question, and only Jesus Christ has ever actually done it. Hopefully, it means turning from our more scandalous sins and endeavouring to find, root out, and kill remaining sin, and finally dying before getting even close to completion.
I do not at all mean to imply that homosexual sin is not a particularly serious sin that a Christian must fight. But, placing that fight against the sin prior to conversion is sending an prospective believer into combat unarmed. Christianity is not primarily a suppression of sinful desires but an embrace of a savior infinitely greater than anything this life has to offer. Jesus offers far more than any sin can. To the extent we can see Jesus as He truly is, we have a means to resist a sin that separates us from Him.
Here is another related thought. Consider the viewpoint of someone deep in the homosexual community. They have heard many conflicting things. Conservative Christians tell them the way they believe the are (homosexual) is intrinsically sinful. (It is, just as all of us were deeply sinful in a number of ways before coming to Christ) But, many liberal Christian voices (who generally treat them better) tell them that only a few cultural-specific verses in the Bible talk about homosexuality, and they can't apply to us because God is all love and rainbows. Anyone on this board is theologically astute enough to discern the teaching of scripture on this issue correctly, but very few young believers would be able to discern which way of reading the bible is right.
Yes, some in the homosexual community genuinely recognize their lifestyle as sinful. God may use this knowledge of sin to lead them to the forgiveness He freely offers. They may well immediately renounce and leave the lifestyle they are in. Others may initially be confused as to which Christian voices to listen to. They will require time to learn to read the scriptures correctly and see that a major area of their life is not in conformity to God's law. This understanding won't always come quickly since many who claim to be Christians today teach that it is acceptable using complicated and complex arguments. I am concerned that many conservative churches would not give them the time to reach that understanding before sending them down the street to a love and rainbows "church."
Let me go back to the prideful person I started with that we are witnessing to. It is possible that convincing him that his pride is a great sin may drive him to seek God's forgiveness. Or, he may not recognize pride as a sin at all. To the extent he compares himself with other human beings, and remains blissfully ignorant of the God of the Bible, he may blindly not see his pride as a problem. Fruitful evangelism can still take place if he can see sin in his life and his need for forgiveness from a just God. As a Christian, that individual will see his insignificance compared to God, and his complete dependence on God. Pride is incompatible with a Biblical understanding of God and man and especially of the gospel.
I took the time to write this because I see a tendency to treat homosexual sin differently than we treat more socially acceptable sins among believers (i.e., the sorts of sins we are susceptible to ourselves.) Without lessening the seriousness of this form of sin, I do pray that we are better able to reach sinners in this particular community.