What? It most certainly is wrong to think that a believer is not bothered by the sinful habits of others. Even Lot was vexed by the people's filthy conversations in his own town.
Scripture says, have no fellowship with the unfruitful works of darkness, but rather reprove them. So lets say Bob struggled with drinking, and after meeting Jesus, he then decides to go to a bar to hang out with his buddies who drink. Not a very smart idea if he still could be tempted to drink again. Oh wait. But that's okay. Bob can go back to being a drunk if you wanted to. It really doesn't matter in the grande scheme of things. For once a son always a son, right?