They don’t have much power to down multiple places so they targeted one to show off, watch our reaction and see how vulnerabilities get fixed. It’s probably one person or a thread on some chan-board taking offense at LW\Lemmy for some reason, and c/shitposting could be taken by activity\moderators count metrics rather than for having something against it alone. They did damage and locked community, but what’s next? If they are indeed like old boards’ posters, methodically flooding communities one after another doesn’t make sense and gets old really quick if they can’t do something more atrocious, achieve new goal or find another exploit. That’s done already.