It's all about practical reasoning. What do you have to gain from association with the Witlesses? Chances are, all they are going to do is hound you into going back to a stagnant life, and they want you to keep going to all those afternoon- and evening-wasting meetings instead of getting on with your life. And there are those rules that you have to obey that further hold you back. Any association with them is going to drag you back into that, since they are programmed to build the cult at any cost.
Even if you are not disfellowshipped, continuing to associate with the Witlesses is going to bind you to their stagnation trap. All they want out of you is to get you to go to the meetings. Given that, you are supposed to progress to rejoining the Theocraptic Misery "School(??)" and give talks that reinforce erroneous beliefs that you once held. Then they are going to focus on getting service out of you. All the while, the original reason why you become inactive is still going to be there. You will only get sucked into stagnation by continuing to associate with Witlesses since they are going to hound you and report any "violations" to the hounders for further hounding.
Ethics aside, I see no reason not to shun the Witlesses. The association is not creating any value whatsoever, and they are trying to get you to destroy value. And that's reason enough to shun them. With the exception, of course, of family members to which you feel any desire to continue associating with.