I suspect Google is included in the lawsuit because they have deep pockets, and could be persuaded to settle for a modest sum rather than bring stats about their error-correction program into court. (They probably do correct quite a bit, although I am pretty sure I can find them showing some through routes in my area that are no longer so, and their search is not what it used to be...but that's another story.)
From the WaPo article, the original private development corporation that owned the road dissolved, and the local officials don't seem to be quite clear who owns title to it now. Out in the country, I would expect that this is normally taken care of by the township roadmaster dumping a berm across the road and driving away; the fact that he didn't hints to me that the de facto owners would have sued and/or shot him if he tried. (Or maybe he's just not very on the ball.) But there doesn't seem to be any prominent posting of the road as private, from what little I can see in that photo; having an unposted road on your property that in all respects appears to be public and leads to a broken bridge seems grossly negligent.