Well to be fair, these accounts cannot flag limitlessly due to their massive amount of flags draining their voting power away (which is in part why their flags are so meaningless). I don't really see how we could have a system that allows to flag users that have no content. Maybe we could try to have some sort of flagging that effects the voting power of the flagged user but this would probably get abused easily. The big problem in the scenario we are witnessing right now comes from Steemit Inc. and nothing else. It kinda shocks me to see how easy it is to go through their account creation system with throwaway emails and phone numbers, especially when we know how long it takes to get verified. What's happening during that verification process if it's not spent verifying that the user is legit. What is even more frustrating is that this could be easily stopped by Steemit Inc. by simply undelegating the Steem Power delegated to these bot accounts, this would effectively make them useless since they couldn't interact with the blockchain. But since Steemit Inc. doesn't seem to care...