Largely because they're residential botnets in places like Brazil (a real example from one of my sites that was crawled to near-destruction). Someone could probably do something about this, but it's out of reach for individual site owners.
replyIf you block Brazil, they'll find an alternative, maybe then you can sue them.
replyBut they operate from neither. You can at most sue the one renting them IP addresses. Which will do basically nothing.
reply(Also, blocking a whole country is likely not what you do, but you probably know that).
Why do you think you can only use the one who's renting them IP addresses?
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