There's no double standard, just randomness. We don't come close to seeing everything. When a bad post hasn't been moderated, the likeliest explanation is simply that we haven't seen it yet.
We've scolded kuschku plenty of times for breaking the guidelines in the past, and you're quite right that he did so there with that uncharitable swipe.
By the way, I (the user you had replied to) fully support your phrasing, and even your comment — my original comment was a bit unstructured, so your question was valid, as it was easy to miss if someone doesn't know the German system.
So I am especially disappointed by the downvotes and the unasked for moderator action your comment got — it asked a valid question.
Please don't take swipes like that in HN comments.