This story has nothing to do with Roadside memorials to people killed in traffic accidents.
This is a story of war protesters using the names of dead GI's for the purpose of anti-war protests.
They are denigrating these soldiers for their own political purposes.
As for Roadside memorials to those killed in accidents, that has become a bit over played also. A cross with a persons name on it might serve some useful purpose in preventing auto accidents by pointing out the fact that driving is dangerous and that people can die from others mistakes, but some of these memorials go way overboard.
That was posted to show the legality or non-legality of such displays. To my way of thinking, they are roadside obstructions and have no standing as property.