Where this bitter, condemning spirit prevails, even persons who are promoting the right KIND of behavior may promote it FOR THE WRONG REASONS. They may correctly identify some action as sinful, but horribly botch the job of explaining WHY that action is sinful.
One area where this happens a lot is the area of sexual purity. Too many preachers have given only one reason why God would be against sexual sin: BECAUSE PEOPLE ENJOY IT. Just that, without further explanation. So the take-away is that if you feel ANY pleasure that has ANY connection with earthly life, it MUST be evil. I'm not exaggerating. One anger-driven pastor in my experience claimed that a boy and girl doing nothing more sensual than HOLDING HANDS were behaving just as sinfully as if they fornicated. This was almost forty years ago, so by now that pastor has probably had to report in at the judgment seat of Christ and have his work evaluated. Of course I don't know, but I would be VERY surprised to learn that in all of his career he ever helped EVEN ONE PERSON to walk in a truly God-centered purity -- for what I know of his preaching serves only to illustrate why worldly people find it so easy to claim that Christianity is "hateful" by its very nature.
When I talk about the Christian standard for sexuality, I talk about how our sex-related conduct AFFECTS OTHER PEOPLE. Both physical sexual intercourse, and the emotional interaction that leads to it or follows after it, will create EXPECTATIONS in the minds of those involved. Unfortunately, the expectations formed in the woman's mind are often TERRIBLY different from those in the man's mind, so that at least one of the partners will end up disillusioned and hurt. Usually the woman. This is only one of the ways in which people may injure other people when sex is in the picture; but this whole area of CONSEQUENCES needs to be more widely understood.
A man who would laugh at you for telling him, "Pleasure is evil BECAUSE it's pleasant," might nonetheless have enough conscience in him that he would stop to think if you told him instead, "SELFISHNESS is evil, because it hurts others who have the same right to be treated well as you have." If the entire world were a church, maybe it would always be enough to say, "Don't do this, because God says not to do it;" but since the entire world ISN'T a church, we need to provide a REASON for being against certain actions.