The problem is that we live in a post christian society which doesn't believe sin is sin any longer. Therefore, everyone is hypersensitive about sin because they don't want people telling them they can't do what they want to do. 100 years ago there was generally a social consensus about what sin was and preaching about sin, righteousness, and the holiness of God was far more common than today.
I get what you are saying. We don't like to be told that we are in sin. I have been one of those who hate to be told that I am in sin. I have a couple of besetting sins that are almost impossible to stop. I have gone after Christians because I do not like to be told that I am in sin. But at the same time it does seem like when they preach against sin they do it in a very self-righteous way. I mean, you have Christians going into Target screaming at the top of their lungs about how sinful everybody is just for shopping at Target. There was this one Christian lady who was politely trying to talk to some of those Christians and they asked her who she was. And she told them that she was a Christian. And they said you are not a Christian. It hurts to see Christians accuse each other this way. But I also get that we don't like to be told that we are in sin as well. Me calling those Christians self-righteous, arrogant, and just plain false Christians is in itself self-righteous and very are hypocritical, because of my besetting sins.
But I also realize that who cares if they are doing it out of self righteous and arrogance. Paul said he didn't care if people preached out of selfishness or not, as long as the name of Jesus Christ was being glorified. Jesus also told the disciples to obey the Pharisees even though they are hypocritical. So I think it's a good thing to tell me when I am in sin, even if it's done to make themselves look more righteous and holy. Because if I listen and put my trust in Jesus Christ and turn from my sin it will be life. But whether they are self-righteous or not that is between them and God. But it is offensive to me when Christians accuse each other of not being true Christians because of another person's weakness or because their philosophy is different than theirs.
Paul was constantly reprimanding the church because of their sins, but he never accuse them of not being true Christians. Although he did say anybody who lives a sinful lifestyle will not inherit the Kingdom of Heaven. Actually, to be perfectly honest I am a little confused with Paul. He told the Galatians that Division and fighting is of the flesh; and those who live in such lifestyle will not inherit the Kingdom of Heaven as well. And yet, the early church lived that kind of Lifestyle. But he still did not accuse them of not being true Christians. I don't know.
I do believe that we are supposed to preach against sin as long as we realize that according to scripture everyone deserves death including the person that is preaching. Some people get the impression that some of those preachers act like they are perfect. That's the impression of the world. Now, I had the same impression, which was because I was in sin myself. Well, I still have sin in my life. But I desire to change.
That's why I also asked the question if Paul was here on Earth preaching, would we accuse him of self-righteousness? I probably would. I have Impressions on Christians, but my impressions are of the flesh. Yes, it does seem like the church can be very self-righteous, but that is my sin. I need to give that up to God. Jesus probably would have seemed very self-righteous to me as well.