The German government hasn't declared them not to be art either and as long as they haven't the real question is whether a court would consider them to be art. I think there is a very good chance that a court would consider them to be art but I don't see it coming to that anytime soon.
A lot of gamers seem to be happy with versions that have these symbols replaced and everyone else simply imports them (which is as simple as ordering from amazon.co.uk instead of amazon.de). Publishers have simply no incentive to pursue this and because violence in games can be censored, publishers censor a lot of games on their own already anyway. I would not be surprised to learn that there are companies even profiting from the current situation.
Right, I used government to broadly. Nevertheless that games are not art is the opinion of that agency. As you already mentioned there interpretation of the law is somewhat shaky here.
Nevertheless to my understanding if a publisher were to get a game censored by the OLJB due to forbidden symbols, the publisher could go to court and I think they would have a decent chance at winning such a case.
A lot of gamers seem to be happy with versions that have these symbols replaced and everyone else simply imports them (which is as simple as ordering from amazon.co.uk instead of amazon.de). Publishers have simply no incentive to pursue this and because violence in games can be censored, publishers censor a lot of games on their own already anyway. I would not be surprised to learn that there are companies even profiting from the current situation.