I think they make the point that they want active JW's to shun inactive JW's who they know have committed something that the elders should deal with. I.e. If you know the inactive JW is living with someone they're not married to, or if they know they're living a homosexual lifestyle, etc. If they're just inactive but not necessarily committing an disfellowshipping offense, then you might still not be subject to shunning. But of course there's going to be some speculation and confusion anyway.
And some JW's just shun anyway, because well, that's what JW's do. If you're inactive, somethings up and you're not good association anyway. Since I stopped going to meetings about 2 years ago not a single person from our hall has stopped by to say hello except for an elder on a shepherding call.