It's nothing more than words. The reason a person is no longer one of Jehovah's Witnesses means nothing - da'd/df'd - the punishment is all the same so what does it matter? I could care less if you tell me someone was ousted for smoking, drinking or immorality or if they left because they just didn't believe in the crap any longer. I'm not about to judge anyone by watchtower standards and for them, shunning is to be applied to the person regardless of the reason they are no longer 'one of them'. They see it all as only black and white.
I break it down into levels. If you are a JW, baptized, in good standing and an elder lets say.....your rating is an 11 - with 10 being the highest and 1 being the lowest.
If you are a worldly person - you are a level 0.
If you are disfellowshipped you drop immediately to a level 1 - only because you can repent and get reinstated. You are after all imperfect so you make mistakes, but you can work toward righting those wrongs. You'll be judged every step of the way and even after, shunned and cast out, but heck - it's only loving discipline.
If you are dissasociated, I figure you drop to a -1. You left Jehovah willingly so Satan has you by the neck and is squeezing. Again you will be judged and shunned.
Now - if you are a disfellowshipped person who ends up with a worldly person, then you are quite obviously not repentent and have now entered the worldly theme park, where women strip naked for your pleasure all day and your nights are fueled by booze and porn. Satan has fooled you into believing that the world is a good place. The shunning would likely get worse and the judgement still stands. You have now moved to a level of -2 - especially if after being df'd and being in the world, you now want to DA yourself because you realized when you were DF'd that it's all a load of crud anyway. sammieswife.