1) who votes on good comments 2) who votes on whose comments 3) who votes a lot / a little.
But mostly (1).
I take your point about ML being superficial. But if it's being used at all, shouldn't the users be informed about what the robo-brain thinks of them?
Your excellent example of a rewording might fool a lot of humans too (see pg's article another commenter linked to ... Ctrl+F "DH4").