Well .. just take a look at what you wrote - it's totally negative. What skin is it off your nose if the guy converts to Islam .. and I don't know where you're getting that information.
There is not one positive statement in your post at all - why. All you are focused on is this "purpose driven" stuff. You need to take a break from it.
Besides .. if it's GOD you won't be able to stop it and if it's not - it will die of it's own accord - GOD knows how to take care of HIS own.
We are told to take up our cross, deny ourselves, turn from sin....many will say "Lord, Lord" who do not know Him. How can we tell who knows Him? If they keep His commandments. You know the verses. God still hates sin, and repentance is fundamental to the gospel. We aren't saved by works, but part of believing is believing what God says about sin. A "broken and contrite heart" he will not ignore. That theme is consistent -- OT & NT.