It's fairly common for these things to appear, and also surprisingly common for them to last a long time after they come to light, unless a Grade AA stink is made about it. As a general rule, Google won't remove something like this directly from their index unless they "have to", and will instead add it to the training/test set for their "bad result" model and will then wait until the models take it down themselves (if they ever do).

Though if this post gets enough attention, it'll probably get fixed in a few days.