Exactly! Their are many in the truth, even now who was some of those things you mentioned. 1 Cor 6:9 and 10 mentions fornicators, men who lie with men, theives and etc. The key as we all know is in verse 11 which says "that is what some of you were", but you have been washed clean and santicified...
A very good friend of mine, we grew up together, both our fathers were elders, all our families are in the truth, however he was disfellowshiped, became a homosexual, and now does women's hair for a living, with tight black pants, tight black turtle necks, flashy gucci belt buckles, and thick soled Kenneth Coles. It's upsetting and sad to me, but as a good friend of his, i'm still here in the truth, not a homosexual. I guess what i'm saying is that we all constantly have thoughts and inclinations contrary to Jehovah's expressed will. But just like you replied, we have to fight against them. Those who don't take advantage of the provisions like the meetings, info from the slave, field service, prayer, can easily fall prey to satan's deceptive works, such as the imorality he invented...