I think you’re totally right in saying it’s their privilege. Their platform, their rules.
I’m curious to find out how they’re evaluating duplicate content. Is it an algorithm searching for copy/pasted? Or is it some program similar to what colleges would use to search for plagiarism? And if it’s the second, where is the breaking point? If it scored at 76% similar is that bad but 75% isn’t (just as an example)?