This is one of those discussions that usually goes nowhere. It is a conversation that either gets bogged down in either defensiveness or self-righteousness. I think it is important that we recognize this point before we begin. Otherwise, we will underestimate how difficult it will be to apply this truth when the appropriate time comes.
For an example of this truth in action, consider I Corinthians 6:18
Flee from sexual immorality. Every other sin a person commits is outside the body, but the sexually immoral person sins against his own body.
When Paul says “every other sin” he is obviously saying there is something distinct about sexual sin. Paul is not saying that sexual sin should get a capital “S” or that it takes two cycles in the cleansing stream of Jesus’ blood.
Paul is saying that if the Corinthians understood the unique nature of sexual sin, they would instinctively run from it like a mouse from a cat.
Now we come back to the question, “Why does this discussion become so contentious?” Because we usually learn (by our error or the words of others) about the distinct dangers of a particular sin when we have committed that sin. Paul is talking to the Corinthians about sexual sin, because that was a major struggle for them.
Now the question turns back to us, “Do we have the humility to hear the distinct dangers of our sin or will we become defensive like those people we have been talking about?”
Every sin has distinct dangers. There no “safe” sins, or even “safer” sins. Let us not debate about which poison would be the best to commit spiritual suicide with. Let us be eager students wanting to have our blinders removed to whatever danger we tend to flirt with.