There are many truths that are boiled down to simple direct statements in scripture. I have a friend that calls them wisdom mc-nuggets. Easily consumed pieces of wisdom. (Easy may be an underestimation of learning these truths). The problem is that they are quoted as if they were the only verse in the Bible. Mistaking such context-free insights for the understanding of the teaching of scripture is hazardous.
In the case of sin, it is always the heart and our sinful nature that is the issue. The actions are the outward symptom.
I agree. The tapestry of the Word has countless jewels woven in . If we pull one of those jewels out and focus only on it, we lose sight of the beautiful picture our Lord and His Kingdom make when the tapestry is viewed as a whole.
Refraining from the expression of sin is only edifying if we replace it with edifying thoughts.
As an example: Taking a man out of a nightclub will not make him a better husband if he just finds another expression of his nature. Until he commits to his wife & marriage, he will be lacking. It may be difficult for him to commit while he is clubbing around town, but unless he changes his heart, nothing has really changed.