This all came about because one person was salty and getting blacklisted for spam and plagiarising. They decided that it was in their heads that steemcleaners and abuse-reports that are the spammers and started this juvenile campaign.
So the person setup 'steemit defence league' and paid people to create accounts for him and is using them to downvote many people randomly. If you have gotten downvoted by various acounts, report the names to @guiltyparties who is compiling a list. Those accounts are having their 15sp delegation removed as a consequence.