The law has caught up with that a few decades ago (well before Steam). Pretty much all of those games can legally be advertised in Germany (sale to adults was a

The law has caught up with that a few decades ago (well before Steam). Pretty much all of those games can legally be advertised in Germany (sale to adults was always possible "under the counter"). For some reason the publishers are overcautious. Probably because none of them wants to see a headline "X has fought to allow swastikas and gore in games".