curating usually spreads stake out - by giving it to the authors
DHF give funds to developers, marketers, some sort of charity thing I'm not familiar with, etc. which also spreads stake out, to the extent that they don't sell it (which is equally true of post payouts).
RE: The main excuse for malicious down-voting is "Over-Rewarded Content..." What about the account making $10k+ PER DAY in spam comments?