Content plagiarism and thefts on Amazon KDP Select
The systemic problem here (compare to the similar, wildly unfair situation with "automated DMCA-based content take-downs on YouTube", etc.), is that on-line entities such as Amazon, have tried to automate a process that inherently involves human judgment.
The DMCA process has a perverse incentive for entities with a marginal real case, to have content arbitrarily censored, without anything like due process; whereas, the opposite is the case here, where it is the content owner that doesn't get a fair hearing.
My guess is that if a (living, breathing) Amazon / KDP representative were to get the real author of one of these works, on (say) a Skype video chat channel, and were then to invite the thief(ves) to the same forum in which to establish "who is the real owner of the intellectual property involved", while there might be a very few problematic cases where you had an experienced liar involved, it wouldn't take long for the Amazon rep to figure out who is the legitimate content owner and who is the thief.
For example : "So, Mr. John StoryAbsconder, when was it, again, that you started work on the first draft of this book? Tell me, what changes did you do to the narrative, in between then and when you published it? Oh, and by the way, can you find me one of those first drafts? Just send me a few pages right now, please... and incidentally, can you find me someone, right now, who saw you working on the book?" etc., etc.
What authors need to do (collectively) to stamp out this ugly little scam, is to lean on Amazon, Lulu, Smashwords, the lot of them... and ask for a REAL dispute adjudication mechanism involving REAL human beings. My guess is that the scammers would then go on to some other, more easily-profitable swindle.
Regards