It's probably been exploited for quite a while already, takes a certain time and threshold until these kinds of things fully bubble up to the public.

People who've been affected might not have noticed or cared enough to say/do something.

Maybe some dark-hat's side project finally reached a major milestone and was released?

No idea.

Apparently someone just found out about it and decided to try it out -- it's obviously "new" to a lot of HN'ers as well.